Science Advisory Report  2015/036

Assessment of Capelin in Subarea 2 and Divisions 3KL in 2015

Summary

• Preliminary landings in 2013 and 2014 were 23,755 and 23,173 t, respectively, against a Total Allowable Catch (TAC) in Divs. 2J3KL of 22,771 t.
• Fish harvesters report increased abundance and distribution in all areas, including those that did not support a commercial fishery in 2014, with larger size (both in length and weight) and with higher fat levels.  All these indicators are comparable to that observed in the 1980s.
• The 2013 and 2014 abundance indices of capelin from the spring acoustic survey were the highest values since 1990 at 53.6 and 121.9 billion respectively; about 25 % of peak values recorded in the 1980s.
• Four recruitment indices covering the year classes since 2003 were generally coherent until 2012 but have since diverged. The most recent estimates of the 2012 and 2013 cohorts in the acoustics survey were both the highest since 1996. These cohorts are expected to comprise the majority of spawners in 2015 and 2016.
• Both larval indices of abundance for the 2014 cohort were below average. Other cohorts of similar magnitude have not contributed significantly to the maturing spawner biomass.
• Fall distribution in the last 4 years is reverting to patterns more similar to those exhibited in the late 1980s than that of the last two decades, with the center of mass located further north and west.
• Spring distributions have also returned to patterns common to the 1980s with capelin more abundant in the coastal areas off the Avalon Peninsula and Trinity Bay.  This represents a west and southward shift when compared to the distribution of the last 15 years.
• Capelin vertical migration patterns in the offshore remain attenuated in comparison to those of the 1980s. Since 1991 capelin have generally been found in areas of greater water depth, and in closer proximity to the bottom.
• The mean lengths and weights of capelin sampled from the commercial fishery catch in 2013 and 2014 were the largest since 1990 and similar to sizes found in the late 1980s.  These increased sizes reflect a higher proportion of age 3 spawners in landings.
• The proportion of age 2 capelin found to be maturing increased from 5 % in the 1980s to a peak of 80 % in 2005.  Since 2011 the proportion of age 2 maturing fish has continually declined to a low of 19 % in 2014.  Delayed maturation is associated with slower growth but improved survival of age 2 capelin.
• From the early 1990s through 2010 spawning times have been delayed by as much as four weeks. Peak spawning at index sites at Bryants Cove and Bellevue Beach from 2011-2014 have occurred in early to mid-July, only two weeks later than in the 1980s.
• Stomach fullness indices from the spring acoustic survey indicate that feeding in 2014 was among the poorest in the time series.  Good feeding success in 2011 was associated with increased amounts of copepods and Oikopleura in the spring diet and higher proportions of euphausiids in the fall.
• Survival of larvae produced in 2011 and 2012 has been 2-3 times better than that of any cohort since 2003.  This two year period corresponds to one of increased zooplankton production and improved condition and feeding in adult capelin.
• Feeding and size-at-age information from the capelin acoustic survey in 2014 suggest that feeding conditions this year may not have been as favourable as from 2011-2013.
• Macrozooplankton (> 1mm) biomass returned to near-normal in 2014 after several years of above average levels. Peaks in this size fraction occurred in 2007 and 2011 coinciding with peaks in standardized recruitment indices of capelin.
• Preliminary ecosystem model estimates of consumption of capelin by fish have been increasing since 2010, which is consistent with the increasing abundance observed in the acoustic surveys. However consumption by seals, whales and seabirds have not been updated.
• Given the poorer environmental and feeding conditions seen in 2014, coupled with the below average strength of the 2014 larval cohort, and the importance of capelin as a forage species, it is suggested that a cautious approach to increasing TACs be adopted.

This Science Advisory Report is from the February 3-5, 2015 Status of Subarea 2 and Division 3KL Capelin. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

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