New Zealand sea lion research 2007/08 to 2009/2010 B. L. Chilvers - - PowerPoint PPT Presentation

New Zealand sea lion research 2007/08 to 2009/2010

• B. L. Chilvers

NZ sea lion research objectives Auckland Islands

• Measure Auckland Islands pup

production

• Tag pups produced each year
• Collect data to estimate

survival and reproduction of previously marked female NZ sea lions

• Maintain and update the NZ

sea lion database

• Characterise and analyse the at-

sea distribution of poorly known age and sex classes of NZ sea lions

Pup production - methods and date

• f estimate
• Sandy Bay (Enderby Island)
• Mark/Recapture estimate

(16/1)

• Dundas Island -

Mark/Recapture estimate (21/1)

• S.E. Point (Enderby Island) -

Direct count -daily counts

• Figure of 8 Island - Single

direct count - (9/1 or 10/1)

Pup production - Results

4 1 5 7 48 55 151 1218 1369 21 364 385 09/10 6 8 14 6 48 54 67 1065 1132 12 289 301 08/09 5 13 18 2 72 74 123 1512 1635 23 425 448 07/08

5 19 24 3 67 70 106 1587 1693 23 414 437 06/07 4 20 24 7 55 62 232 1349 1581 39 383 422 05/06 6 31 37 4 79 83 74 1513 1587 30 411 441 04/05 13 39 52 1 86 87 120 1749 1869 34 473 507 03/04 17 26 43 5 89 95 336 1555 1891 80 408 489 02/03 6 21 27 6 90 96 361 1395 1756 83 320 403 01/02 8 47 55 2 92 94 346 1802 2148 35 527 562 00/01 13 37 50 6 131 137 124 2039 2163 24 482 506 99/00 17 42 59 9 100 109 229 1957 2186 40 473 513 98/99 dead alive total dead alive total dead alive total dead alive total

South East Point Figure of Eight Island Dundas Island Sandy Bay Season

AUCKLAND ISLANDS PUP PRODUCTION 1999-2010

1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 1 9 9 8 / 9 9 1 9 9 9 / 2 / 1 2 1 / 2 2 2 / 3 2 3 / 4 2 4 / 5 2 5 / 6 2 6 / 7 2 7 / 8 2 8 / 9 2 9 / 1 Year Total Pup Production

Pup counts – Sandy Bay

Sandy Bay

100 200 300 400 500 600 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Year Total pup production

Pup counts – Dundas Island

Dundas Island

1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Breeding season Number of Pups

Pup counts - Figure of Eight Island

Figure of Eight

10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Breeding season Number of pups

Pup counts - SEP

South East point

10 20 30 40 50 60 70 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Breeding season Number of pups

Pup Mortality

5 10 15 20 25 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Year % Mortality

Pup Mortality – Sandy Bay

5 10 15 20 25 30 35 40 45 97/98 98/99 99/00 00/01 01/02 02/03 03/04 04/05 05/06 06/07 07/08 08/09 09/10

Year Percentage pup mortality

Pup mortality 1 month Pup mortality 2 months

Dates, tag number, satellite tag id, sex, age, weight, length, girth, number of days deployed and number of satellite locations received from juvenile sea lions captured

1157 71 91 156 77.5 2 M 49094 8179 30/01/2010 247 12 111 157 89 3 M 76964 7260 28/01/2010 569 31 125 209 150 5 M 54760 5752 28/01/2010 143 7 100 152 68 3 F 76965 7584 24/01/2010 222 16 98 153 73 3 F 98814 7458 15/01/2010 209 16 107 154 78.5 3 F 76963 7199 15/01/2010 206 17 84 135 54 2 F 49094 8023 25/01/2009 149 9 83 138 53 2 F 89574 7445 25/01/2009 235 19 93 157 70 3 F 76963 6536 20/01/2009 570 38 92 155 76 3 M 54761 6218 20/01/2009 139 13 104 160 81 3 M 54760 6214 20/01/2009 316 25 84 140 54 2 F 76965 7610 19/01/2009 208 12 98 159 85 3 M 67260 6485 19/01/2009 135 10 98 165 79 3 F 76964 6363 15/01/2009 105 13 90 140 57 2 F 49093 7458 15/01/2009 138 14 107 184 117 5 M 1757 4907 11/01/2009 39 4 96 154 84.5 3 F 54759 6059 26/01/2008 217 11 95 156 68 3 F 54761 5913 25/01/2008 322 31 91 146 73.5 2 F 67259 6463 25/01/2008 26 2 89 152 68 3 F 54756 5863 24/01/2008 183 14 92 141 71 3 F 76966 5857 18/01/2008 248 17 87 153 68 3 F 76964 6130 17/01/2008 309 16 106 177 102 5 M 54760 3727 14/01/2008 7 2 100 164 83 4 M 54757 5093 14/01/2008 366 49 126 184 134.5 4 M 49095 5051 14/01/2008 215 14 108 180 103.5 5 M 49094 4121 14/01/2008 Number of satellite locations Days Girth (cm) Length (cm) Weight (kg) Age Sex Satellite tag id Tag Date

2008 2009 2010 Estimated distribution of juvenile NZ sea lions (satellite locations/10 x 10 km area January & February)

Low Med High Tow start positions /10km2

Low Med High Tow start positions /10km2

2008a 2009a 2010a 2008b 2009b 2010b

a) The distribution of fishing effort in the 6T squid trawl fishery (tow start positions/10 x 10 km area, February to June ot close of fishery 2008-2010) in the Auckland Islands 6T area (Scale 1-10 locations or tows per area (Low), 11- 20, 21-30 (Med), 31-40, 40+ (High)). b) The estimated interaction probability between juvenile NZ sea lion distribution and fishing activities for each year are presented in 3b (Scale 1 (Low), 2, 3-4 (Med), 5-6, 7 (High)).

Low Med High Interaction probability

2008a 2009a 2008b 2009b 2010a 2010b

a) The spatial distribution of scampi fisheries (October to June each season) and b) all other tows recorded in other fisheries for each season 2008, 2009, 2010 in the Auckland Islands 6T area (Scale 1-10 locations or tows per area (Low), 11- 20, 21-30 (Med), 31-40, 40+ (High)). Circles indicate the only areas where overlap with juvenile NZ sea lion satellite locations occur.

Low Med High Tow start positions /10km2

Juvenile at sea distribution

• Most juvenile NZ sea lions (≤4 yrs old) foraging distributions close

to Auckland Islands, predominantly N and NE areas.

• There was significant overlap between juvenile NZ sea lion foraging

locations and squid 6T fisheries activities.

• Which, as does occur, is likely to result in fisheries/juvenile sea lion

interactions and deaths of sea lions.

• There was little overlap of juvenile NZ sea lion from Enderby Island

with scampi or other fisheries activities in the area.

• Similar to adult female NZ sea lion foraging studies, the current 12-

nautical-mile (22-km) marine protected area (MPA) around the Auckland Islands would only protect the entire foraging area of two juvenile female NZSLs

• Exposing 77% of juvenile animals tracked here to fisheries

interactions and bycatch death.

2010-2011 Field Objectives: 1) Collect field data that will allow quantification and estimation of:

• sea lion pup production
• survival of previously marked NZ sea lions
• reproduction by known-age female NZ sea lions

2) Maintain and update NZ sea lion database

Field Trip Logistics First Team: 3 people Leave Bluff 2nd December 2010 Return ~ 13th January 2011 Second Team: 6 people Leave Bluff 7th January 2010 Return ~ 20th February 2011

Pup production field data - methods and date of estimate

• Sandy Bay (Enderby Island)
• Mark/Recapture estimate

(16/1/11)

• Direct count & daily counts
• Dundas Island -

Mark/Recapture estimate (21/1/11)

• S.E. Point (Enderby Island) -

Direct count & daily counts

• Figure of 8 Island - Single

direct count - (10/1/11)

Pup tagging

• All pups at Sandy Bay and SEP will be double flipper

tagged with blue DALTON super tags.

• 400 pups from Dundas Island (300 female and 100

males) will be double flipper tagged with yellow DALTON super tags.

• As many pups as possible will be double flipper tagged

with red DALTON super tags at Figure of Eight Island (numbers of pups tagged restricted due to location logistics).

Collect field data to allow quantification and estimation of:

• survival of previously marked NZ sea lions
• reproduction by known-age female NZ sea lions

* Daily resightings of previously tagged and branded animals at SEP & Sandy Bay between early Dec & late Feb. * Opportunist sightings collected from Figure of Eight & Dundas Island. * Opportunist sightings collected from islands in the Ross Harbour and Auckland Island mainland. * At the time of resighting tag number, tag colour, number of tags, date of sighting, location and reproductive status are recorded. * When possible animals double tag scares will have their PIT tags read. * All sightings will be added to the NZ sea lion database.