pelagic longline take reduction team update: abundance and mortality september 16 2010 dr. lance p....

Pelagic Longline Take Reduction Team Update: Abundance and MortalitySeptember 16 2010

Dr. Lance P. Garrison

Dr. Patricia Rosel

Southeast Fisheries Science Center

Abundance Estimate

(CV)Nmin

Potential Biological Removal

Combined Short-finned and Long-

finned(2009 SAR)

31,139 (0.27) 24,866 249

Long-finned pilot whale

(Draft 2010 SAR)12,619 (0.37) 9,333 93

Short-finned pilot whale

(Draft 2010 SAR)24,674 (0.45) 17,190 172

Revised Abundance Estimates: Draft 2010 SAR

Average Mortality and Serious Injury (combined) 2004-2008: 175 (CV = 0.14)

Splitting Abundance Estimates: Approach

Analytical Approach: Logistic regression to predictthe probability of a sample being from shortfin(or longfin) pilot whale based on location of sample, waterdepth, surface water temperature, surface chlorophyll

Habitat Data: Remotely sensed habitat SST (1 km) and CHL (4km) 8-day composites used to extract values based on sample location/collection date. Bottom depth from 1-minuteresolution bathymetry grid.

Prediction: Predict the probability that an observed groupof pilot whales is of a particular species based on environmental conditions at sighting location. Use thisprobability to partition abundance estimates from 2004surveys.

Year Month Long-finned Short-finned Total

1998 July 55 0 551998 August 2 0 22001 August 1 0 12004 June 0 6 62004 July 45 27 722005 July 6 77 832006 July 0 87 872006 August 0 3 32007 July 1 0 12007 August 11 17 28

TOTAL 121 217 338

Pilot Whale Abundance Estimates: Biopsy Samples from June-August

Includes both Field Collection and Bycatch

Pilot Whale Abundance Estimates: Biopsy Samples from June-August

Pilot Whale Abundance Estimates: Logistic Regression Results

Best model included Depth, SST and their Interaction effect

Pilot Whale Abundance Estimates: 2004 Summer Pilot Whale Sightings

All sightings in the NEC aerial surveys are expected to be long-finned pilot whales.Abundance estimate:11,038 (CV = 0.4)

All sightings in the SEC ship survey are expected to be short-finned pilot whalesAbundance estimate:21,056 (CV = 0.5)

Sightings in the NEC ship survey are in the mixed zone.

Pilot Whale Abundance Estimates: Probability of Being Short-finned

SpeciesBootstrap

Mean Abundance

Bootstrap 95% Confidence

Limit

Short-finned

3,618 1,112 – 8,294

Long-finned

1,581 130 – 5,307

Pilot Whale Abundance Estimates

Survey Latitude Range SpeciesAbundance estimate

(CV)

Atlantic Cetacean Survey (SEFSC )

28° N to 38° N Short-finned 21,056 (0.52)

Northeast Cetacean Survey - Vessel (NEFSC)

38° N to 41° N MixedSF - 3,618 (0.50)

LF - 1,581 (0.86)

Northeast Cetacean Survey - Aerial (NEFSC )

41° N to ~45° N Long-finned11,038(0.40)

Total Abundance Estimates (CV)Short-finned 24,674 (0.45)

Long-finned 12,619 (0.37)

Pilot Whale Abundance Estimates

Pilot Whale Bycatch and Biopsy Data

Limited Data to Parse Out Mortality Estimates

Longline Observer Biopsy Samples

false killer whale

Risso’s dolphin

SF pilot whale, common dolphin

minke whale

bottlenose dolphin

pantropical spotted dolphin

pantropical spotted dolphinsperm whalepygmy sperm whale

Longline Observer Biopsy Samples

We have received 10 biopsy samples between November 2008 and April 2010

• Wide variety of species• 1 short-finned pilot whale off of New Jersey

Field Identification Genetic IdentificationUnknown marine mammal Sperm whalePilot whale False killer whaleBottlenose dolphin Not run yetRisso’s dolphin Not run yetPantropical spotted dolphin Pantropical spotted dolphinPilot whale sp. Short-finned pilot whaleCommon dolphin Common dolphinUnidentified large whale Minke whalePantropical spotted dolphin Pantropical spotted dolphinDwarf sperm whale Pygmy sperm whale

Observed Interactions - 2009

Quarter CAR FEC GOM MAB NEC NED SAB SAR TUN Total

1 0.00 12.09 9.31 4.10 - - 22.40 22.77 0.00 11.90

2 0.00 6.00 58.25 7.36 0.00 0.00 8.18 42.94 9.42 30.12

3 - 8.38 7.44 9.22 14.36 16.57 4.52 - 0.00 9.24

4 - 10.35 11.53 10.52 28.61 0.00 15.59 32.81 0.00 12.06

Total 0.00 9.54 22.40 9.08 14.11 12.43 11.96 27.42 3.31 15.80

Percent Observer Coverage - 2009

Observed Interactions - 2009

Species DeadSerious Injury Released Alive Total

Pilot Whale 0  2 2 4

Risso's Dolphin  0 2 3 5

Bottlenose Dolphin  0 2 1 3

Common Dolphin 1 0 0 1

Pantrop. Spotted Dolphin 0 4 1 5

Unid. Dolphin  0 0 1 1

Unid. Marine Mammal  0 1 0 1

Total 1 11 8 20

Pilot Whale Bycatch Rates- 2009

Quarter Area2005-2008

CPUE2005-200895% CI

2009CPUE

200995% CI

1 MAB 0.2996 0.1349 – 0.6649 0 -

2 MAB 0.1114 0.0339 – 0.3669 0 -

3 MAB 0.1783 0.1065 – 0.2984 0.0208 0.0041 – 0.1065

3 NEC 0.0091 0.0019 – 0.0443 0.0272 0.0053 – 0.1389

4 MAB 0.1148 0.0596 – 0.2210 0.0406 0.0116 – 0.1382

Pilot whale bycatch rates were lower than normal in each quarter. No interactions in quarters 1 & 2. No serious injuries observed in quarter 3.

Risso’s Bycatch Rates- 2009

Quarter Area2005-2008

CPUE2005-200895% CI

2009CPUE

200995% CI

3 MAB 0.0046 0.0009 – 0.0226 0.0242 0.0047 – 0.1239

3 NEC 0.0258 0.0075 – 0.0891 0.0689 0.0245 – 0.1934

3 NED 0 - 0.0274 0.0054 – 0.1401

4 MAB 0.0271 0.0110 – 0.0670 0 -

4 NEC 0.0476 0.0097 – 0.2327 0 -

Risso’s Dolphin bycatch rates were higher in the 3rd quarter, but lower in the 4th Quarter.

Estimated Annual Bycatch - 2009Species Alive

Alive 95% CI

Serious Injury/Mortality

SI 95% CI

Total

Common Dolphin 0 - 8.5 1.7 – 43.4 8.5

Bottlenose Dolphin

11.3 2.2 – 57.6 11.6 3.0 – 44.8 22.9

Pantropical Spotted Dolphin

12.5 2.4 – 63.9 14.0 4.4 – 45.5 26.5

Risso’s Dolphin 27.1 9.1 – 80.9 11.4 3.3 – 39.9 38.5

Pilot Whale 19.2 5.4 – 67.9 16.5 4.8 – 56.8 35.7

Unid. Dolphin 1.6 0.3 – 8.2 0 - 1.6

Unid. Marine Mammal

0 - 8.0 1.6 – 41.2 8.0

Pilot Whale Bycatch and Effort Trends

Risso’s Dolphin Bycatch and Effort Trends

Observed Bycatch Quarters 1 and 2 of 2010

Species Region# Released Un-

injured# Dead # Serious Injury

Pantropical Spotted Dolphin GOM 1 0 0

Unidentified Marine Mammal GOM 0 1 0

Pilot Whale FEC 0 0 1

Minke Whale SAB 1 0 0

Species Region# Released Un-

injured# Dead # Serious Injury

Un-identified Dolphin GOM 1 0 0

Bottlenose DolphinGOM(Exp.)

0 0 1

Unidentified Marine Mammal GOM 0 0 1

Pygmy Sperm Whale GOM 0 1 0

Pilot Whale MAB 0 0 3

Bottlenose Dolphin SAB 1 0 0

Quarter 1

Quarter 2

Observed Bycatch Quarters 1 and 2 of 2010

Quarter Species Area2005-2009

CPUE

2005-200995% CI

2010CPUE

201095% CI

1 Pilot Whale FEC 0 - 0.07020.0137 – 0.3588

1 Pilot Whale MAB 0.27810.1251 –

061880 -

2 Pilot Whale MAB 0.00680.0201 –

0.2220.8403

0.1607 – 4.309

Bycatch Rates Quarters 1 and 2 of 2010

Very high bycatch rate in quarter 2. 3 Pilot whale SI in one set.

Mainline Length in MABBefore and After PLTRP Rule