Fishery Unlikely to Collapse but the Pressure Still On13 March 2012
ANALYSIS - Despite claims that the NorthEast Pacific sardine fishery is facing collapse, Kevin Hill from NOAA's Southwest Fisheries Science Center says the stocks are under pressure but recent data shows population numbers are increasing, writes Lucy Towers, The Fish Site Newsdesk Assistant.
Last week, two researchers from the Southwest Fisheries Science Center in La Jolla, California, suggested that the NorthEast Pacific sardine fishery, which ranges from southeastern Alaska to the Gulf of
California, México, is once again facing collapse.
The researchers, Juan Zwolinski and David Demer, stated that a cooler phase of the oceanic cycle combined with high catches of the breeding stock may cause another fishery collapse as was seen in the 1950's.
Kevin Hill, Research Fishery Biologist at the Southwest Fisheries Science Center, NOAA, told TheFishSite that some scientific aspects of the paper by Mr Zwolinski and Mr Demer are accurate. However, he also stated that for some of the researchers claims there is room for scientific debate.
"The authors' research is just one interpretation based on one method, an acoustical survey that we use to estimate the overall population of sardines," said Mr Hill.
Although the research from Mr Zwolinski and Mr Demer does highlight pressure on the sardine fishery, Mr Hill stated that more recent data collected by the Southwest Fisheries Science Center in the latest stock assessment , after the release of Mr Zwolinski and Mr Demer's report, indicated population growth in the fishery.
"There is no conclusive evidence that this stock is collapsing, but rather that it has more likely been in a declining phase (since the year 2000) of an overall life history strategy that waxes and wanes based primarily on prevailing oceanographic conditions," Mr Hill continued.
The changing oceanographic conditions have been recorded in sedimentary depositions of sardine scales in the Santa Barbara Channel. "These remains have provided evidence of wide sardine population fluctuations over the past 1,700 years, even in the absence of fishing. The causes of their fluctuations can be both environmental and fisheries related," he said.
Although Mr Hill suggests that the sardine fishery will not necessarily collapse there is still pressure on the fishery, which is clearly weakened by both environmental and human impacts.
Mr Hill stated that the fishery has been under increasing pressure. From 2007 to 2011, quotas were cut by 67 per cent in response to the increasing pressure. "Although the US uses a very conservative harvest policy, no formal international management agreement exists for the US, Canada, and Mexico," said Mr Hill. The fishery is therefore under pressure from multiple parties fishing the stock.
Despite the fishery collapse claims from Mr Zwolinski and Mr Demer, the harvest guideline for the sardine fishery in 2012 has more than doubled from 50,526 mt in 2011 to 109,409 mt for 2012. This is due to the population increase seen in the recent data assessment.
Although the recent data points towards stock recovery, the sardine fishery is still fragile and, as before, it could easily collapse again if protection measures are not in place.
In order to protect the fishery and help its recovery, the stock is assessed each year by the Southwest Fisheries Science Center. The assessment process includes annual resource surveys, modeling of survey estimates and fisheries data in a fully-integrated population model, independent peer review of model results, and calculation of a harvest guideline (quota) using the Pacific Fishery Management Councils' (PFMC) control rule.
"The current US harvest rate is about 11 per cent. Among other management objectives, the harvest control was designed to minimise time to recovery during periods of lower productivity and abundance," said Mr Hill.
Following the fishery's collapse in the 1950's the California Department of Fish and Game (CDFG) placed a moratorium on commercial sardine fishing in the mid-1960s, with only minor allowances for sport bait fisheries, said Mr Hill. The sardine population showed signs of recovery in the early 1980s, and minimal directed fishing quotas (ranging 1,000 to 10,000 tons) were implemented throughout that decade. CDFG eventually implemented a harvest control rule that was similar in design to the formula adopted under federal management in 2000.
If further restrictive measures were applied to the sardine fishery fishermen off California's coast would still have opportunities available in the squid and mackerel fisheries. However, the northern fisheries (Oregon and Washington) do not have similar opportunities available and they face a limited fishing season due to weather.