harnessing the sun: testing a novel attachment method to

Harnessing the Sun: Testing a Novel AttachmentMethod to Record Fine Scale Movementsin Ocean Sunfish (Mola mola)

Jonathon D.R. Houghton, Nikolai Liebsch, Thomas K. Doyle,Adrian C. Gleiss, Martin K.S. Lilley, Rory P. Wilson and Graeme C. Hays

Abstract Ocean sunfish (Mola mola) are a little studied fish species which areprone to exceptionally high levels of incidental by-catch. To facilitate future studiesof this species we report on a novel method for short-term deployments of high-resolution data loggers to ocean sunfish. Trials were conducted under captive (n =1 fish) and field conditions (n = 3 fish) during 2006 and 2007 in County Kerry,Ireland. Our principal aims were: (1) to develop a low-impact harness system withan automated release mechanism; (2) retrieve the detached devices at sea; (3) toassess whether this approach enabled the collection of fine-scale behavioural datafrom multi-channel data loggers (daily diaries). Both the attachment and retrievalmechanisms worked well at sea with the successful relocation of all devices. Theharness additionally functioned well by keeping the data logger in a fixed-positionat all times (except during periods of extremely fast evasive swimming) with highresolution data retrieved for a range of variables suggesting significant potential foruse on other fish species. Nonetheless, as each deployment was < 2 h it was not ourobjective to critically define the behaviour of ocean sunfish, but simply to obtainqualitative data upon which to base future studies. Despite the short-term deploy-ments, provisional analysis revealed some unusual swimming behaviour suggest-ing that body roll, in addition to pitch and sway amplitude was intrinsically linkedwith vertical velocity whilst the allometric relationship between body sway and fre-quency (taken as a proxy for fin strokes) appeared converse to previous studies ofteleost locomotion.

Keywords Daily diary · Data logging · Teleost · Ireland · Fish tagging

J.D.R. Houghton (B)School of Biological Sciences, Queen’s University Belfast, Medical Biology Centre,97 Lisburn Road, Belfast BT9 7BL, UKe-mail: [email protected]

N. Liebsch (B)Institute of Environmental Sustainability, School of the Environment and Society,Swansea University, Singleton Park, Swansea SA2 8PP, UKe-mail: [email protected]

J.L. Nielsen et al. (eds.), Tagging and Tracking of Marine Animals with Electronic Devices,Reviews: Methods and Technologies in Fish Biology and Fisheries 9,DOI 10.1007/978-1-4020-9640-2 14, C© Springer Science+Business Media B.V. 2009

229

230 J.D.R. Houghton et al.

Introduction

The movements and behaviours of wide-ranging marine species have been wellelucidated by data-logging or transmitting devices (e.g. Marshall 1998; Wade etal. 2006; Metcalfe et al. 2006; Biuw et al. 2007, Hays 2008). Within the studyof migratory fish this has led to the widespread use of ‘T-bars’ or ‘anchors’ toattach electronic devices whereby nylon (or metallic) darts attached to a leaderare inserted into the muscle (e.g. Sims et al. 2003; Cartamil and Lowe 2004).This approach has proved invaluable in broad-scale studies as it allows devicesto remain attached to study animals for protracted periods. Many of these studieshave used pop-off satellite tags to elucidate long-range movements in species asdiverse as Atlantic bluefin tuna (Thunnus thynnus; Block et al. 2001), white sharks(Carcharodon carcharius; Boustany et al. 2002) and New Zealand long-finned eels(Anguilla dieffenbachia; Jellyman and Tsukamoto 2002). Although fundamental toour current understanding of migratory fish, satellite tracking cannot reveal the finerdetails of behaviour at sub-second resolution, owing to limited bandwidth withinthe Argos satellite system, and as yet do not integrate bespoke sensors to recordchanges in swimming behaviour. Consequently, fine scale studies of swimmingbehaviour in the field require the deployment of data-logging devices that recordmultiple variables at high temporal and parameter resolution including swim speed,body orientation and tail beat frequency (Wilson et al. 2008; Gleiss et al. 2009).Where acceleration is included in the list of parameters to be measured, devicesneed to be attached in a fixed position and/or orientation, rendering the tether andanchor approach unsuitable. To measure swim speed such devices must also bedirectly exposed to the water further negating the encasement of devices withinthe body cavity of large fish (Tanaka et al. 2001, Wilson et al. 2008). Moreover,there is the additional problem of how to remotely detach and recover the deviceitself.

Here we explore a solution to the problem of attaching devices in a fixedposition to ocean sunfish (Mola mola). Our principal aims were to test the useof an inert silicone elastomer to construct a flexible yet robust harness and tosee whether this approach alowed us to acurately record fine-scale behaviouraldata.

Methods

Captive Trails

A soft harness was constructed from an inert silicone elastomer (Silastic R© DowCorning Corporation, USA) (Fig. 1). This constituted a narrow strap, which waspotted inside a ∼10 mm tube (cut half open along its length) resulting in one flatand one curved side, to fit around the animal and a buoyant device housing weigh-ing ∼60 g in air (without any associated data logging device). A silastic pocket (to

Recording Fine Scale Movements in Ocean Sunfish 231

Fig. 1 Schematic showing silastic harness attached to sunfish showing (a) position of magne-sium burn wire and (b) position of data logger on opposite side. (c) three metres of monofil-ament line served as a connector between the harness and the dan buoy. When the fish wasactively swimming the buoy was rigged so that it was towed ‘flat’ to minimise drag. (d) Oncethe burn-wire had corroded the harness rose to the surface so that it did not weigh the dan-buoy down. The buoy floated at the surface so that the radio transmitter could be raised 30 cmabove the water to prevent radio signals being blocked by surface swell or waves. (e) juvenileocean sunfish fitted with a silastic harness in an open-water tank at Dingle Ocean World (MaraBeo) during captive trials. (f) Measuring and fitting harness in a sea water tank aboard researchvessel

house the DD) was additionally constructed and attached to the strap using a flexiblerubber resin (Fig. 1). Captive trials were conducted on a small sunfish (TL = 69 cm,dorsal to anal fin tips = 95 cm) held in a large open-air tank (10 m wide, 1.2 mdeep), and given 24 h to acclimatise (Fig. 1) after initial wild capture. The fish wasmeasured and the harness cut to size (body circumference minus 2 cm) so that thetwo open sides of the harness were held together by a cable tie in front of the dorsalfin with only minimal stretch (Fig. 1). A ‘daily diary’ (DD) data logger (75 × 35 ×20 mm; weight: 45 g) recording at 8 Hz on all channels was then inserted into thedevice housing (Fig. 1). DD data loggers are multi-channel data-loggers that directlyor indirectly measure four main elements: animal location and movement, animalbehaviour, energy expenditure and environmental conditions (see Wilson et al. 2008and Shepard et al. 2008 for full descriptions). To assess the suitability of harnessattachments we restricted our analysis to four specific data channels, namely: (1)depth; (2) body pitch; (3) body roll; and (4) body sway dynamic (i.e. the lateralsway of the body resulting from individual fin strokes). Lastly, to assign specificbehaviours to distinct patterns within the output of these four channels equippedsunfish were monitored visually and with a digital camcorder from an elevated plat-form (3 m) at the side of the pool.


Field Trails

During August 2007 we conducted short-term field trials of the silastic harness onfree-living ocean sunfish in County Kerry, Ireland. At this stage the harnesses wereslightly modified from the captive trials by incorporating an upper and lower saddleand an attachment point for a galvanic timed release mechanism (Neptune MarineProducts, Washington, USA). All parts were potted separately and assembledafterwards using a flexible rubber resin. Sunfish were caught from a rigid inflatableboat using a 9 sqm OR 3 × 3 mm2 cast net and transferred immediately to a plasticsea water tank on-board a larger supporting vessel (MV Miss Fiona) (Fig. 1). TheDDs were programmed to record at 8 Hz on all available channels. Measurementsof body circumference and final fitting of the harness were made whilst the fishwas submerged in the tank (diameter: ∼1 m; height: 1.2 m). The harnessed fishwas then passed back to the rigid inflatable boat where it was immediately releasedat sea level. From capture till release the tagging procedure took approximatelyfourteen minutes.

The galvanised burn wires were filed down to give deployment duration of ∼2 hafter which they would snap apart, releasing the sunfish from its harness. Time forrelease was only approximate as the rate at which the galvanised wire dissolves insea water is directly related to water temperature which varies significantly through-out the water column at temperate latitudes. To ensure the harness would be slightlypositively buoyant and therefore float to the surface after detachment, micro-bubbles(B-Spheres Gr.2, OMEGA Minerals, Norderstedt, Germany) were embedded withinthe silastic during construction (weight: 165 g). To aid relocation at the surface, asmall (40 × 15 mm, with 30 cm whip antenna) coded VHF radio transmitter (1/3 NFMV Falconry Transmitter; Merlin Systems Inc.) was attached to the top of a small‘Dan buoy’ (length: 60 cm) (Fig. 1). This buoy was then attached to the harnessusing a monofilament line (length 3 m; 200 lb breaking strain), and rigged so thatit towed at an angle parallel to the sea surface to minimise drag (Fig. 1). Radiotransmitters were located using a YAGI antenna.

Analysis of Dive Data

Defining Descent and Ascent Phases

Considering the limited amount of data available, but making use of the high reso-lution of the records to gain the most information, vertical velocity was calculatedover 30 s intervals throughout the dataset. As at this point, periods of considerablechange in depth are of most interest, vertical velocity values between + 0.02 and –0.02 m s–1 were removed from the analyses (Fig. 2a).

We additionally examined the variability in vertical velocity during descent andascent phases (Fig. 2a). Using a step-wise multiple regression (Minitab R© V, 10.51)we simultaneously tested vertical velocity against (1) pitch (2) roll (3) frequencyof body sway and (4) amplitude of body sway (for periods of positive (ascent)and negative (descent) vertical velocities independently). A Mann-Whitney test wasadditionally used to compare median roll angles.


Fig. 2 (a) Sample profile from depth channel of sunfish M3 (see Fig. 4f for full profile) illustratingthe terms descent phase (DP) and ascent phase (AP). 30-s increments represent the sample periodsthat were used to derive multiple mean values (frequency and amplitude) during each descentand ascent phase. (b) Sway dynamic data from sunfish M1 showing the calculation of frequency(F) and amplitude (A) based on methodology of Tanaka et al. (2001). (c) Sway dynamic datafor sunfish M1 immediately after release showing periods of fast evasive swimming followed bynormal swimming behaviour and the harness flapping

Defining Frequency and Amplitude from Sway Dynamic Data

Mean frequency and amplitude of body sway (which can be taken as a proxy ofthe timing and magnitude of fin strokes) were determined from the dynamic swaychannel for each 30 s interval (the same as the vertical velocities). The frequency andamplitude of body sway were defined using the previous definitions of Tanaka et al.(2001) (Fig. 2b). Through comparison with the video footage, we used a thresholdacceleration amplitude of 0.01g (g = acceleration of gravity, 9.81 m s–2) to definefin-strokes.

Results

Captive Trials

The harness was attached to the captive ocean sunfish for 2.5 h. At no time duringthe deployment did the animal appear to be agitated or restricted by the presence


of the harness (e.g. rubbing itself against the side of the tank). To check whetherthe DD remained flat against the body during deployment (a pre-requisite of suchdata logging devices) we examined two specific data channels (the roll and swaydynamic) during periods where ‘normal’ swimming behaviour was identified fromthe digital footage. Both channels revealed that, at the velocities attained by the fishin the aquarium, the DD remained flat against the body confirming the suitability ofthe harness for data logger attachment.

Next, to confirm whether a centrally-placed data logger could reveal swimmingbehaviour (given the unusual body shape of ocean sunfish) we again examined theDD sway dynamic channel. A clearly identifiable signal was detected (mean bodysway frequency = 0.58 Hz) representing the side to side movement of the sunfishas a result of simultaneous beats of the dorsal and anal fins (validated with digitalvideo footage).

Once the harness was free of the captive sunfish we checked for superficial tissuedamage. A small area on the dorsal ridge displayed some discolouration, whichreturned to normal after 24 h. To alleviate this problem we made a mould of a deadjuvenile sunfish (landed as fisheries by-catch; total length = 71 cm; dorsal to anal fintips = 102 cm) using flexible moulding rubber (Mouldsil R©, GRS Glass, Fibre andResin Supplies, Cork, Ireland) and plaster-of-Paris. A cast of the sunfish was thenmade using micro-crystalline wax and pigment (RPM Suppliers, Dublin, Ireland).This model was used to modify the harness so that it incorporated an upper andlower saddle to minimise abrasion at the dorsal and anal ridges (Fig. 1), with anarea cut away in the lower saddle to allow excretion.

Field Trials

In total, three DD deployments were made with the device and harness retrievedsuccessfully in each case. Unfortunately, a software malfunction onboard the sec-ond DD prevented the retrieval of viable data, restricting our analysis to two individ-uals termed M1 and M3. Details of the DD deployments and body measurementsof sunfish are given in Table 1with descriptive statistics for swimming behaviour

Table 1 Deployment details for field trials of harness at the mouth of Smerwick Harbour, CountyKerry, Ireland 16-23/08/2007

S’fish TL1 BH2 D to A3 Time in Trial duration Dist. Viable# Date (cm) (cm) (cm) water4 (h) (km)5 data

M1 22/08 79 47 101 11:30 1.6 5.4 YM2 23/08 69 43 91 13:05 1.8 1.6 NM3 23/08 66 41 87 15.30 1.3 2.89 Y

1Total length2 Body height3 Tip of dorsal fin to tip of anal fin4Local Time (GMT + 1 h)5 Distance between deployment and retrieval site (km)


Table 2a Descriptive statistics for swimming behaviour in sunfish M1 derived from descent andascent phases

Mean vert.Mean speed velocity Mean pitch Mean roll Freq. (g)1 Amplitude

Phase (m s–1) (SD) (m s–1) (SD) (o)(SD) (o) (SD) (SD) (g)2 (SD)

Descent 0.29 (0.08) 0.08 (0.05) –15.0 (5.75) 62.2 (5.53) 0.83 (0.09) 0.03 (0.004)Ascent 0.71 (0.07) 0.07 (0.06) 1.9 (7.37) 72.8 (4.26) 0.86 (0.10) 0.02 (0.04)

Table 2b Descriptive statistics for swimming behaviour in sunfish M3

Mean vert.Mean speed velocity Mean pitch Mean roll Freq. Amplitude

Phase (m s−1) (SD) (m s–1) (SD) (o)(SD) (o) (SD) (g)1 (SD) (g)2 (SD)

Descent 0.29 (0.15) 0.05 (0.03) –8.00 (4.39) –3.2 (23.5) 0.72 (0.08) 0.08 (0.01)Ascent 0.48 (0.07) 0.04 (0.03) 1.5 (6.04) 5.8 (27.3) 0.69 (0.08) 0.08 (0.02)

1 Frequency of body sway derived from sway dynamic channel2 Amplitude of body sway derived from sway dynamic channel

(speed, roll, pitch, frequency and amplitude of body sway) given in Table 2(a, b).For information of deriving swim speed from DD see Shepard et al. (2008).

The estimated corrosion time of magnesium burn wires proved to be extremelyreliable with constant radio signals (indicative of harness detachment) detectablewithin ∼2 h of initial release. Unlike the captive trials the sway dynamic channel(used as a proxy of fin strokes) revealed two distinct periods of intense movementreaction in both animals after the initial release (Fig. 2c) and prior to final detach-ment of the harness (maximum duration of apparent aberrant behaviour: 80 s) withno such events evident through the rest of the trial periods (Fig. 3d, h). For M1,post-release behaviour (i.e. a significant increase in swim-speed) caused the harnessto lift away from the body and flap laterally for the duration of ∼20 s (Fig. 2c). Thiscould clearly be observed in additional video footage taken during the release andin the data themselves as the positive pitch angles recorded during initial descentwould have required the animal to be pointing upwards if the harness had been inplace.

For M1 vertical velocity during descent or ascent could not be explained by fre-quency or amplitude (p >0.05) with pitch and roll explaining the vast majority ofvariability (Descent phase M1: pitch = 84.76%, roll = 6.92%. Ascent phase M1:pitch = 92.93%, roll = 4.56%). The behaviour of M3 appeared quite different withamplitude additionally explaining variation in vertical velocity (Descent phase M3:pitch = 17.39%, roll = 54.04%, amplitude = 3.31%. Ascent phase M3: pitch =45.91%, roll = 17.55%, amplitude = 6.31%). Based on mean values calculatedover the 30 s intervals (Fig. 2) the relationship between roll and vertical velocity isgiven in Fig. 4. This illustrated a difference between study animals with M3 shift-ing between different sides of the fish facing upwards, whilst M1 appeared to be


Fig. 3 Example of raw data output from daily diaries for sunfish M1 (a–d) and M3 (e–h). Datashown are for entire deployments from time of release to final detachment of harness. (d, h)dynamic sway showing reaction of sunfish to initial release (R) and just prior to detachment ofharness (HD)

consistently rolled to the left when ascending or descending. To investigate this dif-ference further, roll data for M3 were separated into negative (descent) and positive(ascent) vertical velocities. An Anderson-Darling test (Minitab R© V. 10.51) revealedthat roll angles during both phases were not normally distributed (p >0.05). Usinga Mann-Whitney test to compare median roll angles, a difference in roll between


Fig. 4 Mean roll angleversus mean vertical velocity(from 30-s intervals) for M1(•) and M3 (o) (note distinctskew of M1). Positive anglesindicate the animal is rolledover to the left, negativeangles to the right

phases (W = 2509, p <0.05) became apparent with the fish orientated more tothe left during descent (20.15◦; IQR −26.05–31.83◦) and to the right during ascent(–6.50◦ (IQR –25.75–21.25)).

To examine the interaction of propulsive forces we then correlated fin-beat fre-quency with swaying acceleration amplitude using mean data derived from the 30 ssample periods. This revealed a significant quadratic relationship indicating thatbody sway amplitude typically decreased as a function of respective fin-beat fre-quency (M1: F2,103 = 37.12, r2 = 0.42, p <0.05; M3: F2,116 = 92.30, r2 = 0.61, p<0.05).

Discusssion

Recent advancements in data-logging devices have enabled workers to gatherbehavioural and environmental data for marine vertebrates in a manner never beforepossible (e.g. Schreer et al. 2001; Butler et al. 2004; Hays et al. 2004; Houghtonet al. 2008). Consequently, there is unprecedented scope for applying such tech-nology to a host of ecological and conservation related issues for a wide range ofspecies (Cooke et al. 2004, Ropert-Coudert and Wilson 2005, Ellwood et al. 2007).This potential is clearly demonstrated in the ocean sunfish as their lack of commer-cial value in parts of the world beyond the Asian market has served to greatly restricttargeted studies of their ecology and behaviour (Sims and Southall 2002; Houghtonet al. 2006). Thus, although extraordinary numbers of these poorly understood fishare killed each year in by-catch, we have little or no idea as to the overall ecosys-tem response to such activity (Silvani et al. 1999). Recent studies have attemptedto redress this lack of information using acoustic telemetry (Cartamil and Lowe2004), molecular techniques (Streelman et al. 2003) and aerial surveys (Houghtonet al. 2006), yet continued efforts are required if we are to unravel the behaviouralecology of this enigmatic species.


Under this overarching goal of gathering simple behavioural data for ocean sun-fish, the harness method detailed here may enable researchers to conduct furtherfine-scale studies of a variety of species. However, this approach comes with a num-ber of caveats given that the use of harness systems has been rendered redundantin the biotelemetry of many marine vertebrates. For example, leatherback turtles(Dermochelys coriacea) equipped with directly-attached satellite transmitters haverecently been shown to swim further and faster than other turtles fitted with moretraditional harnesses, with the overall inference that direct attachment reduces dragand thus energy expenditure (Fossette et al. 2008). However, this was an extensiveoceanic tracking programme which differs markedly from the short-term deploy-ments described here. Under this scenario, the secured attachment of the loggingdevice and its detachment provide an effective and less intrusive solution for stud-ies where data cannot be remotely relayed. However, the use of a harness is notthe only solution for short-term deployments of fixed-position data loggers andwhere it is not imperative that the device be retrieved manually other techniquessuch as directly suturing the device to the animal may be more appropriate (Simset al. 2001). The applicability of the harness method to other large pelagic fishalso requires additional thought given the ‘flapping’ that was detected just after therelease of animal M1 (Fig. 2c). As this was a period of accelerated swimming sug-gesting that the ability of the harness and data logger to remain flush against theside of the fish may be compromised above a threshold velocity. Knowing this, thedesign and shape of the harness and especially the DD-housing could be modifiedfor future deployments to reduce drag even further and prevent such flapping. Theintense movement recorded during the release of the system is most likely due tothe process of the fish freeing itself from the harness once the galvanic timed releasemechanism has detached the ends.

Additional trials of the harness method are also required to define conclusivelywhether inconsistencies in body orientation (particularly roll) are not related tothe presence of the device or tether. For example, it is not entirely clear whetherthe particular bias of M1 for rolling to the left is an actual artefact of its natu-ral behaviour or an attempt to dislodge the harness. Additionally, one might alsoconsider the possibility that the harness simply slipped during deployment. Weare confident, however, that neither biases contributed to the observed bias in ori-entation as the friction of the silastic on the rough skin of a sunfish holds it inplace and the design of the saddles (cut-out in the middle to fit closely around thefins) prevent any sideways sliding. Additionally, there is no place on the under-side of a sunfish (only a few cm wide), which could possibly result in such areading.

Some insight into this difference comes from the distance travelled by thetwo animals with M1 apparently moving further away from the deployment site(Table 1) possibly suggesting that the consistent roll to the left may be indicative ofcontinual swimming. Additionally, the tendency for ocean sunfish to orientate withone side upwards was also evident for M1 and is well documented for the speciesas a whole (Schwartz and Lindquist, 1987; Sims and Southall 2002; Houghton et al.2006).


We further consider that the attachment of the DD to the side of the sunfish accu-rately captures high resolution data on body orientation and the propulsive natureof swimming behaviour (Fig. 3). This constitutes an essential step towards the con-struction of energy budgets and foraging models for this particular species (Wilsonet al. 2008). Following on from this pilot study, we will attach DD for periods ofdays through to weeks (which is well within the capabilities of the harness), in con-junction with time depth recorders deployed on their jellyfish prey (Hays et al. 2008)to answer questions regarding survival on this low energy food source (Doyle et al.2007) and the exact nature of sunfish surface basking behaviour (Fraser-Brunner1951; McCann 1961; Schwartz and Lindquist 1987).

In terms of behaviour itself, the immediate effects of tagging marine species arewell documented (e.g. Watanuki et al. 1992; Wilson and McMahon 2006; Sherrill-Mix and James 2008) and it is generally considered appropriate to remove datafrom the first day from any analyses (Sundstrom and Gruber 2002). In this pilotstudy it was not our objective to critically define the swimming behaviour of oceansunfish, but to demonstrate a particular method by which such data may be obtainedin future studies. Nevertheless, a number of generic statements can be made fromthe present data such as the somewhat intuitive relationship between body pitch andvertical velocity. The importance of roll and sway amplitude is less straightforwardto interpret and future studies should seek to describe these factors in more detail.

From these provisional data, however, it is evident that sunfish utilise roll farmore extensively than would be expected for a teleost which may partially explaintheir unusual shape. One reason might be, that they show higher roll angles to makeuse of their large lateral surface area to reduce their sinking rate and accomplish ahigher horizontal displacement at the same time. This would explain why the high-est roll angles were recorded at relatively slow vertical velocities. The relationshipbetween the frequency and amplitude of body sway also raises interesting questionsgiven that the allometry of fin-beat frequency appears to be reversed in ocean sunfish

Fig. 5 Relationship betweenbody sway frequency andamplitude derived from thesway dynamic channel forM1 (•) (total length: 79 cm;total height: 101 cm) and M3(o) (total length: 66 cm; totalheight: 87 cm)


(i.e. larger frequencies observed in the larger fish), when compared to most fishwith a lateral propulsive system (Fig. 5) (Bainbridge 1958, Gleiss et al. 2009). Thedecrease in the amplitude of body sway with increasing frequency is also unusual,as one would expect higher frequencies to have larger amplitudes (see Gleiss et al.2009).

Bringing these findings together, our pilot data from both captive and field studiesfully support the use of silastic harnesses for the deployment of data loggers toocean sunfish, and the effectiveness of centrally-placed devices to reveal fine-scalebehavioural data. In turn we hope that this study draws attention to this alternativemethod which, with careful design and consideration, may have great potential forsimilar studies of other large pelagic fishes.

Acknowledgments Funding was provided through grants from the Marine Institute Ireland (TKDJDRH) National Parks and Wildlife Service (Ireland) and NERC (MKSL), Udarus Na Gaeltachta(TKD); Taighde Mara Teo and Rolex (NL RPW). For logistical support we are extremely gratefulto: Mark Norman and Vincent Roantree from Taighde Mara Teo and Padraig F. O’Suilleabhainfrom Ecotours (Ballydavid) for research vessel support; Kevin Flannery and Maria Laguna fromMara Beo (Dingle Oceanworld) for aquarium facilities and support; Vincent Highland for videosupport; Ben Reilly (artist) for making the mould and wax cast of the sunfish; J-U Voigt, EmilyShepard, Victoria Hobson and Maude Coudert for design and construction of the harness. Theconstructive comments from Nuno Fragoso and three anonymous referees were also greatly appre-ciated.

References

Bainbridge R. (1958) The Speed of Swimming of Fish as Related to Size and to the Frequency andAmplitude of the Tail Beat. J. Exp. Biol. 35, 109–133.

Biuw M. Boehme L., Guinet C., Hindell M., Costa D., Charrassin J.-B., Roquet F., Bailleul F.,Meredith M., Thorpe S., Tremblay Y., McDonald B., Park Y.H., Rintoul S.R., Bindoff N.,Goebel M., Crocker D., Lovell P., Nicholson J. and Fedak M.A. (2007) Variations in behaviourand condition of a Southern Ocean top predator in relation to in situ oceanographic conditions.Proc. Nat. Acad. Sci. 104, 13705–13710.

Block B.A., Dewar H., Blackwell S.B., Williams T.D., Prince E.D., Farwell C.J., Bosutany A.,Teo S.L.H., Seitz A., Walli A. and Fudge D. (2001) Migratory Movements, Depth Preferences,and Thermal Biology of Atlantic Bluefin Tuna. Science. 293, 1310–1314.

Boustany A.M., Davis S.F., Pyle P., Anderson S.D., Le Boeuf B.J. and Block B.A. (2002) Expandedniche for white sharks. Nature. 415, 35–36.

Butler P.J., Green J.A., Boyd I.L. and Speakman J.R. (2004) Measuring metabolic rate in the field;the pros and cons of the doubly labelled water and heart rate methods. Funct. Ecol. 18, 168–183.

Cartamil D.P. and Lowe C.G. (2004) Diel movement patterns of ocean sunfish Mola mola offsouthern California. Mar. Ecol. Prog. Ser. 266, 245–253.

Cooke S.J., Hinch S.G., Wikelski M., Andrews R.D., Kuchel L.J., Wolcott T.G. and Butler P.J.(2004) Biotelemetry – a mechanistic approach to ecology. Trends. Ecol. Evol. 19, 334–343.

Doyle T.K., Houghton J.D.R., McDevitt R., Davenport J. and Hays G.C. (2007) The energy densityof jellyfish: Estimates from bomb-calorimetry and proximate-composition. J. Exp. Mar. Biol.Ecol. 343, 239–252.

Ellwood S.A., Wilson R.P. and Addison A.C. (2007) Technology in conservation: a boon but withsmall print. In: Macdonald D, Service K (eds) Key Topics in Conservation Biology. BlackwellPublishing, Oxford, pp. 105–119.

Fossette S., Corbel H., Gaspar P., LeMaho Y. Georges J-Y. (2008) An alternative technique for thelong-term satellite tracking of leatherback turtles. End. Spec. Res. Doi: 10.3354/esr00039.


Fraser-Brunner A. (1951). The ocean sunfishes (Family Molidae). Bull. British Mus. (Nat. Hist.)Zoo. 1, 87–121.

Gleiss A.C., Gruber S.H. and Wislon R.P. (2009) Multi-channel data-logging: towards deter-mination of behaviour and metabolic rate in free-swimming sharks. In: Nielsen, J.L.,Arrizabalaga, H., Fragoso, N., Hobday, A., Lutcavage, M., Sibert J. (eds.), Tagging and Track-ing of Marine Animals with Electronic Devices. Springer, Vol. 9, ISBN: 978-1-4020-9639-6.

Hays G.C., Doyle T.K., Houghton J.D.R., Lilley M.K.S., Metcalfe J.D. and Righton, D. (2008)Diving behaviour of jellyfish equipped with electronic tags. J. Plankt. Res.

Hays G.C. (2008) Sea turtles: a review of some key recent discoveries and remaining questions. J.Exp. Mar. Biol. Ecol. 356, 1–7.

Hays G.C., Metcalfe J.D., Walne A.W. and Wilson R.P. (2004) First records of flipper beat fre-quency during sea turtle diving. J. Exp. Mar. Biol. Ecol. 303, 243–260.

Houghton J.D.R., Cedras A., Myers A.E., Liebsch N., Metcalf J.D., Mortimer J.A. and Hays G.C.(2008) Measuring the state of consciouness in a free-living diving sea turtle. J. Exp. Mar. Biol.Ecol. 356, 115–120.

Houghton J.D.R., Doyle T.K., Davenport J. and Hays G.C. (2006) The ocean sunfish Mola mola:insights into distribution, abundance and behaviour in the Irish and Celtic Seas. J. Mar. Biol.Assoc. UK. 86, 1–7.

Jellyman D. and Tsukamoto K. (2002) Fist use of archival satellite transmitters to track migratingfreshwater eels Anguilla dieffenbachia at sea. Mar. Ecol Prog. Ser. 233, 207–215.

Marshall G.J. (1998) Crittercam: an animal-borne imaging and data logging system. Mar. Technol.Soc. J. 32, 11–17.

McCann C. (1961) The sunfish Mola mola in New Zealand waters. Rec. Dominion Mus. 4,7–20.

Metcalfe J.D., Hunter E. and Buckley A.A. (2006) The migratory behaviour of North Sea plaice:currents, clocks and clues. Mar. Fresh. Behav. Physiol. 39, 25–35.

Ropert-Coudert Y. and Wilson R.P. (2005) Trends and perspectives in animal-attached remote sens-ing. Front. Ecol. Environ. 3, 437–444.

Schreer J.F., Kovacs K.M. and Hines R.J.O. (2001) Comparative diving patterns of pinnipeds andseabirds. Ecol. Monog. 71, 137–162.

Schwartz F.J. and Lindquist D.G. (1987) Observations on Mola mola basking behaviour, parasites,echeneidid associations, and body-organ weight relationships.J. Elisha Mitchell Sci. Soc. 103 ,14–20.

Shepard E.L., Wilson R.P., Liebsch N., Quintana F., Gomez Laich A. and Lucke K. (2008) Flexiblepaddle sheds new light on speed: a novel method for the remote measurement of swim speedin aquatic animals. End. Spec. Res. doi: 10.3354/esr00052.

Sherrill-Mix S.A. and James, M.C. (2008) Evaluating potential tagging effects on leatherback seaturtles. End. Spec. Res. doi: 10.3354/esr00070.

Silvani L., Gazo M. and Aguilar A. (1999) Spanish driftnet fishing and incidental catches in thewestern Mediterranean. Biol. Cons. 90, 79–85.

Sims D.W., Nash, J.P. and Morritt, D. (2001) Movements and activity of male and female dogfishin a tidal sea lough: alternative behavioural strategies and apparent sexual segregation. Mar.Biol. 139, 1165–1175.

Sims D.W. and Southall E.J (2002) Occurrence of ocean sunfish, Mola mola near fronts in thewestern English Channel. J. Mar. Biol. Assoc. UK. 82, 927–928.

Sims D.W., Southall E.J., Richardson A.J., Reid P.C. and Metcalfe, J.D. (2003) Seasonal move-ments and behaviour of basking sharks from archival tagging: no evidence of winter hiberna-tion. Mar. Ecol. Prog. Ser. 248, 187–196.

Streelman J.T., Puchulutegui C., Bass A.L., Thys T., Dewar H. and Karl S.A. (2003). Microsatel-lites from the world’s heaviest bony fish, the giant Mola mola. Molecular Ecol. Notes 3,247–249.

Sundstrom L.F. and Gruber S.H. (2002) Effects of capture and transmitter attachments onthe swimming speed of large juvenile lemon sharks in the wild. J. Fish Biol. 61,834–838.


Tanaka, H., Takagi, Y. and Naito, Y. (2001) Swimming speeds and buoyancy compensation ofmigrating adult chum salmon Oncorhynchus keta revealed by speed/depth/acelaration data log-ger. J. Exp. Biol. 204, 3895–3904.

Wade P., Heide-Jørgensen M.P., Shelden K., BarlowJ., Carretta J., Durban J., Le Duc R., MungerL., Rankin S., Sauter A. and Stinchcomb, B. (2006) Acoustic detection and satellite-trackingleads to discovery of rare concentration of endangered North Pacific right whales. Biol. Lett. 2,417–418.

Watanuki Y., Mori Y. and Naito, Y. (1992) Adelie penguin parental activities and reproduction:effects of device size and timing of its attachment during chick rearing period. Polar Biol. 12,539–544.

Wilson R.P. and McMahon C.R. (2006) Measuring devices on wild animals: what constitutesacceptable practice? Front. Ecol. Environ. 4, 147–154

Wilson R.P., Shepard E.L.C. and Liebsch, N. (2008) Prying into the intimate details of animal life:use of a daily diary on animals. End. Spec. Res. doi: 10.3354/esr00064

harnessing the sun: testing a novel attachment method to

Documents