Historical and contemporary diet of northern fur ?· Historical and contemporary diet of northern fur…

Download Historical and contemporary diet of northern fur ?· Historical and contemporary diet of northern fur…

Post on 26-Aug-2018

212 views

Category:

Documents

0 download

TRANSCRIPT

<ul><li><p>Historical and contemporary diet of northern fur seals in the North Pacific</p><p>Rolf R. Ream and Tonya K. ZeppelinNational Marine Mammal Laboratory</p></li><li><p>Overview</p><p> Summarize at-sea diet using multi-national historical data sets</p><p> Describe contemporary food habits from U.S. islands</p><p> Address spatial and temporal variability in diet</p></li><li><p>Robben Island</p><p>Kuril Islands</p><p>Commander Islands</p><p>Bogoslof Island</p><p>Pribilof Islands</p><p>San Miguel Island</p><p>Russia North America</p><p>Northern fur seal distribution and breeding sites</p></li><li><p>Food Habits Data Sources</p><p> Historical: pelagic collections (stomachs) Japan Russia United States</p><p> Contemporary: breeding islands (scats and spewings) United States</p><p> Percent occurrence (PO) of prey =% of samples w/ prey X out of all samples w/ prey</p><p> Primary prey</p></li><li><p>Pelagic DataSpatial and Temporal Coverage</p><p> Japan Western North Pacific (January-June, 1953-1991)</p><p> Russia Commander Islands (June-November, 1965-1982) Sea of Okhotsk (June-August, 1964-1981) Sea of Japan (February-May, 1961-1976)</p><p> United States (ranging from 1958-1974) California (February-May, 1958-1966) Washington/Oregon (February-May, 1958-1972) British Columbia (February-May, 1958-1968) Gulf of Alaska (February-May, 1958-1968) Bering Sea (August-September, 1960-1974)</p></li><li><p>Japanese and Russian Pelagic Collections</p></li><li><p>Japan - Top four prey</p><p>Japanese collections (Jan-June, n=4029)</p><p>0</p><p>5</p><p>10</p><p>15</p><p>20</p><p>Lantern fish Japanese fireflysquid</p><p>Mackerels andtunas</p><p>Japanes sardine</p><p>Perc</p><p>ent o</p><p>ccur</p><p>renc</p><p>e</p><p>Japanese Collections</p><p>010</p><p>2030</p><p>4050</p><p>6070</p><p>8090</p><p>1953 1955 1957 1959 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Lantern fish Japanese firefly squidMackerels and tunas Japanes sardine</p></li><li><p>Russia - Top five prey by regionCommander Islands </p><p>(June-November, n = 561)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>Walleye pollock Salmon Hexagrammidae(Atka mackerel)</p><p>Pacif ic sandlance</p><p>Berryteuthismagister</p><p>Perc</p><p>ent o</p><p>ccur</p><p>renc</p><p>e</p><p>Sea of Okhotsk(June-August, n = 204)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>Walleyepollock</p><p>Salmon Gonatusfabricii</p><p>Myctophidae Berryteuthismagister</p><p>Perc</p><p>ent o</p><p>ccur</p><p>renc</p><p>e</p><p>Sea of Japan (February-May, n= 1132)</p><p>01020304050607080</p><p>Walleye pollock Berryteuthismagister</p><p>Perc</p><p>ent o</p><p>ccur</p><p>renc</p><p>e</p></li><li><p>PO by year</p><p>Commander Islands (June-November, n = 561)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>Walleye pollock Salmon Hexagrammidae(Atka mackerel)</p><p>Pacif ic sandlance</p><p>Berryteuthismagister</p><p>Perc</p><p>ent o</p><p>ccur</p><p>renc</p><p>e</p><p>Sea of Japan (February-May, n= 1132)</p><p>01020304050607080</p><p>Walleye pollock Berryteuthismagister</p><p>Perc</p><p>ent o</p><p>ccur</p><p>renc</p><p>e</p><p>Commander Islands</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>70</p><p>80</p><p>1965 1967 1969 1971 1973 1975 1977 1979 1981Pe</p><p>rcen</p><p>t Occ</p><p>urre</p><p>nce</p><p>Walleye pollock SalmonHexagrammidae (Atka mackerel) Pacific sand lanceBerryteuthis magister</p><p>Sea of Japan</p><p>0102030405060708090</p><p>100</p><p>1961 1963 1965 1967 1969 1971 1973 1975</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Walleye pollock Berryteuthis magister</p></li><li><p>PO by yearCommander Islands</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>70</p><p>80</p><p>1965 1967 1969 1971 1973 1975 1977 1979 1981Pe</p><p>rcen</p><p>t Occ</p><p>urre</p><p>nce</p><p>Walleye pollock SalmonHexagrammidae (Atka mackerel) Pacific sand lanceBerriteuthis magister</p><p>Commander Islands (June-November, n = 561)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>Walleye pollock Salmon Hexagrammidae(Atka mackerel)</p><p>Pacif ic sandlance</p><p>Berriteuthismagister</p><p>Perc</p><p>ent o</p><p>ccur</p><p>renc</p><p>e</p><p>Sampling:</p><p> location</p><p> month</p><p>Sea of Japan (February-May, n= 1132)</p><p>01020304050607080</p><p>Walleye pollock Berryteuthismagister</p><p>Perc</p><p>ent o</p><p>ccur</p><p>renc</p><p>e</p><p>Sea of Japan</p><p>0102030405060708090</p><p>100</p><p>1961 1963 1965 1967 1969 1971 1973 1975</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Walleye pollock Berryteuthis magister</p></li><li><p>U.S. Pelagic Collections(n=7,933)</p></li><li><p>U.S. - Top five prey or &gt;10% POby region during winter migration (February-May)</p><p>California (n=2097)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>Pacif ic hake Northernanchovy</p><p>Market squid Clubhooksquid</p><p>Pacif ic saury</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Washington/Oregon (n=2670)</p><p>0</p><p>10</p><p>20</p><p>Pacif icherring</p><p>Northernanchovy</p><p>Marketsquid</p><p>Clubhooksquid</p><p>Gonatidsquid</p><p>Rockfish</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>British Columbia, Canada (n=382)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>Pacificherring</p><p>Sablefish Salmon Walleyepollock</p><p>Gonatidsquid (B.magister)</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Gulf of Alaska (n=968)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>Pacif icherring</p><p>Pacif ic sandlance</p><p>Capelin Walleyepollock</p><p>Gonatidsquid</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p></li><li><p>PO by month (all years combined)</p><p>California (n=2097)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>Pacif ic hake Northernanchovy</p><p>Market squid Clubhooksquid</p><p>Pacif ic saury</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Washington/Oregon (n=2670)</p><p>0</p><p>10</p><p>20</p><p>Pacif icherring</p><p>Northernanchovy</p><p>Marketsquid</p><p>Clubhooksquid</p><p>Gonatidsquid</p><p>Rockfish</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>California</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>Feb(n=1006)</p><p>March(n=558)</p><p>April(n=268)</p><p>May(n=265)</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Pacific hake</p><p>Northernanchovy</p><p>Market squid</p><p>Clubhooksquid</p><p>Pacific saury</p><p>Washington/Oregon</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>Feb(n=257)</p><p>March(n=583)</p><p>April(n=1181)</p><p>May(n=649)</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>PacificherringNorthernanchovyMarket squid</p><p>ClubhooksquidGonatidsquidRockfish</p></li><li><p>PO by month (all years combined)</p><p>British Columbia, Canada (n=382)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>Pacif icherring</p><p>Sablefish Salmon Walleyepollock</p><p>Gonatidsquid (B.magister)</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Gulf of Alaska (n=968)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>Pacif icherring</p><p>Pacific sandlance</p><p>Capelin Walleyepollock</p><p>Gonatidsquid</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Gulf of Alaska</p><p>0102030405060708090</p><p>100</p><p>Feb (n=33)</p><p>March(n=205)</p><p>April(n=225)</p><p>May(n=505)</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Pacificherring</p><p>Pacific sandlance</p><p>Capelin</p><p>Walleyepollock</p><p>Gonatidsquid</p><p>British Columbia</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>Feb (n=89)</p><p>March(n=79)</p><p>April (n=44)</p><p>May (n=170)</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Pacificherring</p><p>Sablefish</p><p>Salmon</p><p>Walleyepollock</p><p>Gonatidsquid</p></li><li><p>Washington/Oregon (n=2670)</p><p>0</p><p>10</p><p>20</p><p>Pacificherring</p><p>Northernanchovy</p><p>Marketsquid</p><p>Clubhooksquid</p><p>Gonatidsquid</p><p>Rockfish</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>California</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>1958 1960 1962 1964 1966Pe</p><p>rcen</p><p>t Occ</p><p>urre</p><p>nce</p><p>Pacific hake Northern anchovyMarket squid Clubhook squidPacific saury</p><p>Washington/Oregon</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>1958 1960 1962 1964 1966 1968 1970 1972</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Pacific Herring Northern anchovy Market squidClubhook squid Gonatid squid Rockfish</p><p>PO by year (all months combined)</p><p>California (n=2097)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>Pacif ic hake Northernanchovy</p><p>Market squid Clubhooksquid</p><p>Pacif ic saury</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p></li><li><p>PO by year (all months combined)</p><p>British Columbia, Canada (n=382)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>Pacif icherring</p><p>Sablefish Salmon Walleyepollock</p><p>Gonatidsquid (B.magister)</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Gulf of Alaska (n=968)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>Pacif icherring</p><p>Pacific sandlance</p><p>Capelin Walleyepollock</p><p>Gonatidsquid</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Gulf of Alaska</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>70</p><p>1958 1960 1962 1964 1966 1968</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Pacific herring Pacific sand lanceCapelin Walleye pollockGonatid squid</p><p>British Columbia, Canada</p><p>0102030405060708090</p><p>100</p><p>1958 1960 1962 1964 1966 1968</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Pacific herring SablefishSalmon Walleye pollockGonatid squid (B. magister)</p></li><li><p>Top 5 prey during summer (August-September) in the Bering Sea</p><p>Bering Sea (n=1816)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>Greenlandturbot</p><p>Bathylagidae Capelin Walleyepollock</p><p>Gonatidsquid</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Bering Sea</p><p>0102030405060708090</p><p>100</p><p>1960 1962 1964 1966 1968 1970 1972 1974</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Greenland turbot BathylagidaeCapelin Walleye pollockGonatid squid</p></li><li><p>Breeding IslandsSpatial and Temporal Coverage</p><p> Pribilof Islands, AK 1987-2000</p><p> Bogoslof Island, AK 1997-2000</p><p> San Miguel Island, CA 1980-1986</p><p> Scats and spewings</p></li><li><p>Pribilof IslandsTop five prey by island (August-September)</p><p>St. Paul Island (n=2970)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>70</p><p>Walleyepollock</p><p>Gm/Gm squid Pacif ic sandlance</p><p>Salmon Gb/Bm squid</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>St. George Island (n=1203)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>70</p><p>Walleyepollock</p><p>Gm/Gm squid Northernsmoothtongue</p><p>Salmon Gb/Bm squid</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>St. Paul Island</p><p>0102030405060708090</p><p>100</p><p>1987 1989 1991 1993 1995 1997 1999</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Walleye pollock Gm/Gm squidPacific sand lance SalmonGb/Bm squid</p><p>St. George Island</p><p>0102030405060708090</p><p>1987 1989 1991 1993 1995 1997 1999</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>eWalleye pollock Gm/Gm squidNorthern smoothtongue SalmonGb/Bm squid</p></li><li><p>Bogoslof and San Miguel Islands Top 5 prey or &gt; 10% PO</p><p>Bogoslof Island (n=148)</p><p>0102030405060708090</p><p>Northernsmoothtongue</p><p>Gb/Bm squid Gonatus tinro Walleyepollock</p><p>Northernlampfish</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>San Miguel Island, CA (n=518)</p><p>0</p><p>10</p><p>20</p><p>30</p><p>Pacif ic hake Marketsquid</p><p>Clubhooksquid</p><p>Californialanternfish</p><p>Northernanchovy</p><p>Juvenilerockfish</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>San Miguel Island</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>70</p><p>1980 1982 1984 1986</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Pacific hake Market squidClubhook squid California lanternfishNorthern anchovy Juvenile rockfish</p><p>(1997-2000)</p></li><li><p>Polovina CliffsPolovina</p><p>VostochniMorjovi</p><p>LukaninKitovi</p><p>ZapadniLittle ZapadniZapadniReef Tolstoi</p><p>GorbatchArdiguen</p><p>Reef</p><p>South</p><p>Zapadni</p><p>East CliffsEast Reef</p><p>North</p><p>Staraya Artil</p><p>Foraging areas and dietPribilof Islands</p><p>119 119 trips made by 97 trips made by 97 females, 1995females, 1995--9696</p></li><li><p>Polovina CliffsPolovina</p><p>VostochniMorjovi</p><p>LukaninKitovi</p><p>ZapadniLittle ZapadniZapadni Reef</p><p>Tolstoi</p><p>GorbatchArdiguen</p><p>Reef</p><p>South</p><p>Zapadni</p><p>East CliffsEast Reef</p><p>North</p><p>Staraya Artil</p><p>Rookery complexes based on diet (1987-2000)</p></li><li><p>Pribilof Islands spewing-scat comparison Species composition</p><p>St. George Island</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>70</p><p>80</p><p>Gb/Bm</p><p>Gm/G</p><p>m</p><p>North</p><p>ern Sm</p><p>ootht</p><p>ongu</p><p>ePa</p><p>cific </p><p>Herrin</p><p>g </p><p>Pacif</p><p>ic sa</p><p>lmon</p><p>Pacif</p><p>ic Sa</p><p>nd La</p><p>nce</p><p>Walle</p><p>ye Po</p><p>llock</p><p>Perc</p><p>ent o</p><p>ccur</p><p>renc</p><p>e Scats (n=1,127)Spews (n=204)</p><p>St. Paul Island</p><p>0</p><p>10</p><p>20</p><p>3040</p><p>50</p><p>60</p><p>70</p><p>80</p><p>Gb/Bm</p><p>Gm/G</p><p>m</p><p>North</p><p>ern Sm</p><p>ootht</p><p>ongu</p><p>e</p><p>Pacif</p><p>ic He</p><p>rring </p><p>Pacif</p><p>ic sa</p><p>lmon</p><p>Pacif</p><p>ic Sa</p><p>nd La</p><p>nce</p><p>Walle</p><p>ye Po</p><p>llock</p><p>Perc</p><p>ent o</p><p>ccur</p><p>renc</p><p>e Scats (n=2,317)Spews (n=63)</p></li><li><p>Pribilof Islands spewing-scat comparison Walleye pollock age class distribution</p><p>St. George</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>70</p><p>80</p><p>0 1 2 3 4 5</p><p>Age Class</p><p>FO</p><p>Scats (n=1,484 otoliths in 173 samples)</p><p>Spews (n=105 otoliths in 27 samples)</p><p>St. Paul</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>70</p><p>80</p><p>0 1 2 3 4 5</p><p>Age Class</p><p>FO</p><p>Scats (n=17,827 otoliths in 902 samples)</p><p>Spews (n=154 otoliths in 23 samples)</p></li><li><p>Northern fur seal diet Fur seal distribution extensive = wide range of </p><p>prey consumed Within regions, diversity of prey is low Prey composition differed among regions Affected by the habitat used within a region Variable over months and years, some trends Effects of regime shifts?</p><p> 1977, 1989, 1999 (?) Diet data encompassing periods both before and after </p><p>these events is limited</p></li><li><p>Bering Sea and Pribilof Islands Historical vs. contemporary data</p><p>Pelagic data 1960-1974 Stomachs (n=1,816) Top prey:</p><p>Gonatid squidCapelin</p><p>Walleye pollockGreenland turbot</p><p>Bathylagidae</p><p>Breeding Islands 1987-2000 Scats (n=4,178) Top prey:</p><p>Walleye pollockGonatid squid</p><p>SalmonSand Lance</p><p>Northern smoothtongue</p></li><li><p>Bering Sea and Pribilof Islands Historical vs. contemporary data</p><p> Potential differences and biases in methods Last meal, differential digestion, introduction of </p><p>secondary prey, etc. for scats Not likely to explain current:</p><p> Absence of capelin and Greenland turbot Large increase in PO of walleye pollock</p><p> Opportunistic predators; possibly affected by 1977 and 1989 regime shifts</p><p> Other evidence of environmental signals?</p></li><li><p>Japanese pelagic data and the1977 and 1989 regime shifts</p><p>Japanese Collections</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>50</p><p>60</p><p>70</p><p>80</p><p>90</p><p>1953 1955 1957 1959 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991</p><p>Perc</p><p>ent O</p><p>ccur</p><p>renc</p><p>e</p><p>Lantern fish Japanese firefly squidMackerels and tunas Japanes sardine</p><p>-2.5</p><p>-1.5</p><p>-0.5</p><p>0.5</p><p>1.5</p><p>2.5</p><p>1953 1955 1957 1959 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991</p><p>PDO</p><p> Inde</p><p>x</p><p>PDO Index</p></li><li><p>Signals of environmental change in northern fur seal diet</p><p> Effects of regime shifts not conclusive with limited data</p><p> El Nino events are known to change food habits dramatically for pinnipeds Affect fur seals:</p><p> San Miguel Island breeding colony Seasonal migrants to the west coast of U.S.</p></li><li><p>AcknowledgementsAcknowledgements</p><p> NorihisaNorihisa BabaBabaFisheries Research Agency, JapanFisheries Research Agency, Japan</p><p> ShirohShiroh YonezakiYonezakiNational Research Institute of Far Seas Fisheries, JapanNational Research Institute of Far Seas Fisheries, Japan</p><p> Jim ThomasonJim ThomasonNational Marine Mammal Laboratory, USANational Marine Mammal Laboratory, USA</p></li></ul>

Recommended

View more >