Science Advisory Report  2010/001

Assessment of the Bay of Fundy Sea Urchin Fishery, Lobster Fishing Area 36

Summary

• There has been an increasing trend in the catch per unit of effort (CPUE) for both the dive and drag fisheries since 1991-92. This could be due to improved fishing practices and experience, changing market conditions, or changes in abundance.
• CPUE has elements of population abundance but is influenced by discarding due to product quality and market prices. Therefore, the CPUE series must be interpreted with caution and cannot be used exclusively as an indicator of population abundance.
• For the dive fishery, the number of fishing trips showed an increasing trend from 1999 to 2005 but has been variable in recent years.
• For drag licenses, the number of trips have declined from the 1996-97 fishing year to 2003-04 and has been increasing since.
• With the exception of Deer Island, where legal size sea urchin densities have decreased, all other areas show no statistically significant differences in densities for each size grouping between the 1992-94 and 2002-03 survey periods.
• With the exception of immature urchins (< 25 mm test diameter), the density of urchins was significantly higher in the shallow depth strata (0-10 m).
• Total biomass has changed little between the 1992-94 and 2002-03 survey periods. Estimated fishable biomass appears to have declined, but is not significantly different between the two surveys due to a high degree of variability.
• Based on the established Total Allowable Catch (TAC) of 900 t, the harvesting rate is estimated to be 7.9% -- 1.1% higher than the harvesting rate of 6.8% that was approved in 1996. However, Passamaquoddy Bay area is also fished but has never been surveyed; thus, no biomass estimate for this area is available. For that reason, the 7.9% harvesting rate is an overestimate.
• Implementation of the new logbook format will facilitate collection and analysis of effort and harvesting rate data by fishing area in more detail and on a timelier basis.
• Fishery impacts on the ecosystem with respect to by-catch of non-urchin species and potential impact of urchin fishing on the habitat requires collection and processing of new information.
• The recommended assessment schedule is every 5 years. However, annual monitoring of the landings, fishing effort, and catch rate from the fishing logs would be useful to determine if an earlier than scheduled assessment is required.

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