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This summary provides an overview of the Atlantic swordfish species, including information on stocks, biology, and fishery indicators. It discusses the current state of the stocks, the impact of management regulations, and the outlook for the future.
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Summary of Atlantic Swordfish Species Working Group Discussion (see also SCI -021)
SWO-ATL Background • Both the North and South stocks were assessed in 2006, and the next assessments are anticipated in 2009. • Stocks are considered to be close or at the rebuilt condition, as defined by the Convention objectives.
SWO-ATL 1. Biology (North and South) • Two scientific documents related to swordfish biology were presented: • One document presented an analysis of the genetic and growth patterns of swordfish. The results suggested the presence of three main populations in the Mediterranean, Atlantic and Indo- Pacific. Moreover, in the Atlantic, the authors noted a north to south gradient of increasing membership to the Indo-Pacific cluster (SCRS-07-120) • The second paper addressed the reproductive activity of swordfish in the Atlantic based on different macroscopic indicators. The main conclusions were that the reproductive activity of females appears to be related to the temperatures in the epipelagic layers and is largely restricted to the warm regions of the Western Atlantic. In addition, the size at first maturity of females was estimated to be 146 cm (LJFL). (SCRS-07-111)
SWO-ATL 2. Fishery Indicators (North and South) • Total Atlantic • The total Atlantic estimated catch of swordfish (North and South, including discards) reached a historical high of 38,624 t in 1995 The 2006 estimated catch was 25,127 t (reported catch was 24,288 t). Many countries have not yet reported their 2006 catches so values should be considered provisional. • North Atlantic • For the past decade, the North Atlantic estimated catch (landings plus discards) has averaged about 11,600 t, and the 2006 landings (including carry-overs) plus discards were 11,817 t (reported catch was 11,072 t). • South Atlantic • In 2006, the estimated of 13,310 t catches (13,216 reported) were about 39% lower than the 1995 reported level but 2% higher than the 2005 reported catches (13,071 t).
SWO-ATL 2. Fishery Indicators (North, CPUE) • North Atlantic • Updated CPUE information was provided by Spain (SCRS -07-110), USA (in the WG) and Canada (SCRS-07-134). • The USA and Canadian indices show a decline, but this is slight in the case of the USA and attributable to market factors in the Canadian nominal catch rate series. Information from the Spanish surface longline fleet has indicated a rapid increase of CPUE from 1999 to 2000, and relative stability from 2000 until 2005. USA Canada Canada Spain
SWO-ATL 2. Fishery Indicators (South, CPUE) Sao Paulo • South Atlantic • Two new standardized swordfish CPUE series were presented for Brazilian longliners, based on set by set data, one restricted to the fishing vessels operating from São Paulo and another one encompassing the whole fleet, including São Paulo-based longliners. • While the CPUE of swordfish caught by longliners based in São Paulo State, southern Brazil, showed a decline in 2006, the overall results were similar to those presented in the previous assessment, with the data from the whole fleet confirming a continued trend of CPUE increase in recent years. Entire Fleet
SWO-ATL 3. State of the Stocks (North and South) • North • The 2006 assessment indicated that the biomass at the beginning of 2006 was estimated to be about 99% of the biomass needed to produce MSY and the 2005 fishing mortality rate was estimated to be about 14% below the fishing mortality rate at MSY. • South • The current estimated fishing mortality rate is likely below that which would produce MSY, and the current biomass is likely above that which would result from fishing at Fmsy in the long term. The estimated MSY (about 17,000 t) is 33% higher than current reported landings.
SWO-ATL 4. Outlook (North and South) • North Atlantic • Results from the 2006 assessment indicated that it was likely that the northern swordfish stock is nearly rebuilt to BMSY, although there is some uncertainty associated with this conclusion. Almost half of the bootstrap estimates of current biomass were greater than or equal to BMSY. Projections based on the last assessment taking into account the current agreement (06-02), if fully realized, indicate the stock is likely to decline to below the level that would produce MSY (more details later) • South Atlantic • The 2006 assessment indicated that while the southern swordfish stock appears to be in a healthy condition at present, it is unclear if substantially higher catches than currently envisioned by the Commission could be sustained in the long-run, due to the divergent views of stock status provided by the targeted and by-catch fisheries indicators.
SWO-ATL 5. Effect of Current Management Regulations (North and South) • The SCRS Chair provided a demonstration of the possible consequences of implementation of Rec 06-02. This Recommendation could allow harvests about 1000 t above the estimate of sustainable yield. • If the catch levels identified in the allocation table are fully obtained, there is a possibility that the stock will decline below the convention objectives.
SWO-ATL 6. Management Recommentations (North and South) • North Atlantic • To maintain the northern Atlantic swordfish stock close to a level that would produce MSY, the Committee continues to recommend continuing the present TAC (14,000 t). Given the estimated stock productivity (r=0.49) and MSY (14,100 t), this TAC should be sustainable into the future, and reflects the maximum yield that could be harvested from the population under existing environmental and fishery conditions. • South Atlantic • Until more research has been conducted to reduce the high uncertainty in stock status evaluations for the southern Atlantic swordfish stock, the Committee recommends that annual catch should not exceed the provisionally estimated MSY (about 17,000 t).