We identify changes in the pelagic fish community of the tropical Pacific Ocean by comparing recent data collected by observers on longline fishing vessels with data from a 1950s scientific survey when industrial fishing commenced. A major shift in size composition and indices of species abundance and community biomass accompanied the start of fishing. The largest and most abundant predators, such as sharks and large tunas, suffered the greatest declines in abundance (21%% on average). They also showed striking reductions in mean body mass. For example, the mean mass of blue shark ( Prionace glauca ) was 52 kg in the 1950s compared to 22 kg in the 1990s. The estimated abundance of this species was 13%% of that in the 1950s. Overall, the biomass of large predators fell by a factor of 10 between the periods. By contrast, several small and formerly rare species increased in abundance, e.g., pelagic stingray ( Dasyatis violacea ). However, the increases in small species did not balance the reductions in the biomass of large predators. Of three possible explanations (fishing, environmental variation, and sampling bias), available evidence indicates fishing to be the most likely cause for the observed patterns.
Ecology – Ecological Society of America
Published: Apr 1, 2005
Keywords: abundance ; biomass ; ecosystem stability ; epipelagic zone ; fishery surveys ; longlining ; pelagic environment ; predator–prey interactions
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.
All for just $49/month
Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly
Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.
Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera