Marine Mammals

Marine mammals may be accidentally captured in purse seines. They may also become entangled in longlines or or hooked on them, e.g., false killer whales in the Hawaii-based deep-set longline fishery. In the tropical tuna purse-seine fishery, species such as baleen whales or dolphins (as well the whale shark Rhincodon typus), may serve as sighting cues by purse-seine fishermen for the presence of tuna schools at the surface of the sea and/or may be caught accidentally when fishing for the targeted species [1].

Successful techniques to release marine mammals from purse seine nets have been employed for some time, e.g., the backdown procedure and Medina panel, and there have been advances in techniques for safe handling and release of megafauna from purse seines [2,3]. Progress in the development of dynamic spatial fishery management strategies will help fishers to avoid interactions in the first place. For example, a recent study identified the principal environmental variables influencing the co-occurrence between baleen whales, whale sharks and tuna purse-seine fisheries [1]. Fishing area closures are utilised in the interim. 'Weak' circle hooks and strong branchlines are required in the Hawaii-based deep-set and shallow-set longline fisheries (see NOAA's Whale link below). They can reduce bycatch (but not depredation), though post-interaction mortality is unknown.

SeaLlifeBase is a source of biological and distribution data for marine mammal species. FAO's guide to the Marine Mammals of the World provides species identification and distribution information. Locate handy Species ID guides here. NOAA's 'Find a Species - Dolphins & Porpoises' and 'Whales' has information on protection status, biology and population status, distribution, threats, conservation measures and research.

References

  1. Escalle, L., Pennino, M.G., Gaertner, D., Chavance, P., Delgado de Molina, A., Demarcq, H., Romanov, E., and Merigot, B. 2016. Environmental factors and megafauna spatio-temporal co-occurrence with purse-seine fisheries. Fisheries Oceanography 25(4): 433–447. doi:10.1111/fog.12163.
  2. Escalle, L., Murua, H., Amande, J.M., Arregui, I., Chavance, P., Delgado de Molina, A., Gaertner, D., Fraile, I., Filmalter, J.D., Santiago, J., Forget, F., Arrizabalaga, H., Dagorn, L., and Merigot, B. 2016. Post-capture survival of whale sharks encircled in tuna purse-seine nets: tagging and safe release methods. Aquatic Conservation: Marine and Freshwater Ecosystems 26(4): 782–789. doi:10.1002/aqc.2662.
  3. Poisson, F., Vernet, A.L., Seret, B., and Dagorn, L. 2012. Good practices to reduce the mortality of sharks and rays caught incidentally by the tropical tuna purse seiners. EU FP7, EBFMtuna-2012 Montpellier, France.

 

Dolphins

Species

3-Alpha Code Name Scientific Name
BBW BEAKED WHALE, BLAINVILLE’S Mesoplodon densirostris
BCW BEAKED WHALE, CUVIER'S Ziphius cavirostris
BEW BEAKED WHALE, BAIRD'S Berardius bairdii
BLW BLUE WHALE Balaenoptera musculus
BRW BRIDE'S WHALE Balaenoptera Edeni
CSL SEA LION, CALIFORNIA Zalophus californianus
DBO BOTTLENOSE DOLPHIN Tursiops truncatus
DBZ INDO-PACIFIC BOTTLENOSE DOLPHIN Tursiops aduncus
DCO COMMON DOLPHIN Delphinus delphis
DCZ LONG-BEAKED COMMON DOLPHIN Delphinus capensis
DDU DUSKY DOLPHIN Lagenorhynchus obscurus
DPN DOLPHIN, SPOTTED Stenella attenuata
DRR RISSO'S DOLPHIN Grampus griseus
DSI SPINNER DOLPHIN Stenella longirostris
DSP SPOTTED DOLPHINS Stenella spp.
DST STRIPED DOLPHIN Stenella coeruleoalba
DWP DOLPHIN, PAC. WHITE-SIDED Lagenorhynchus obliquidens
DWW DWARF SPERM WHALE Kogia simus
FAW FALSE KILLER WHALE Pseudorca crassidens
FRD DOLPHIN, FRASER'S Lagenodelphis hosei
GRW GRAY WHALE Eschrichtius robustus
HUW HUMPBACK WHALE Megaptera novaeangliae
KPW PYGMY KILLER WHALE Feresa attenuata
MAM MARINE MAMMAL (UNIDENTIFIED) Mammalia
MEW MELON-HEADED WHALE Peponocephala electra
MIW MINKE WHALE Balaenoptera acutorostrata
ODN TOOTHED WHALES NEI (BLACKFISH) Odontoceti
PDA PORPOISE, DALL'S Phocoenoides dalli
PHR PORPOISE, HARBOR Phocoena phocoena
PIW Long-finned pilot whale Globicephala melas
PYW PYGMY SPERM WHALE Kogia breviceps
RNW DOLPHIN, N. RIGHT WHALE Lissodelphis borealis
RTD DOLPHIN, ROUGH-TOOTHED Steno bredanensis
SEA NEW ZEALAND FUR SEAL Arctocephalus forsteri
SEC SEAL, HARBOR Phoca vitulina
SEK Australian Fur Seal Arctocephalus pusillus
SEN FUR SEAL, NORTHERN Callorhinus ursinus
SGF FUR SEAL, GUADALUPE Arctocephalus townsendi
SHW SHORT-FINNED PILOT WHALE Globicephala macrorhynchus
SIW SEI WHALE Balaenoptera borealis
SMH SEAL, HAWAIIAN MONK Monachus schauinslandi
SNP SEAL, NORTHERN ELEPHANT Mirounga angustirostris
SPW SPERM WHALE Physeter macrocephalus
SSL SEA LION, STELLER Eumetopias jubatus
SXX SEALS Otariidae, phocidae
TGW GINKGO-TOOTHED BEAKED WHALE MesoplodonGinkgodens
WLE WHALE (UNIDENTIFIED) Cetacea