Research Document - 2007/004

Area 9 Herring: a review of available information for stock assessment purposes

By Therriault, T.W.

Abstract

Area 9 is located outside of the Central Coast major herring stock assessment region and includes all of Rivers Inlet. Pacific herring (Clupea pallasi) often are observed in this area but have not been harvested from this area since the reduction fishery that ended in the late 1960s. Some stakeholders have requested harvest opportunities in this area and a review of available information was conducted to provide scientific advice on the feasibility of this request. A review of the population genetic information suggested potential differences from the Central Coast stock but additional years of data are required to confirm this possibility. A review of the catch information was relatively uninformative because all landings were from the reduction fishery period when herring were fished almost year round, often off their spawning grounds. Also, this fishery was plagued by mis-reporting of landing locations that further compromises the limited information available. A review of the spawn data showed the patchiness of this time series and high variability. Also, there was a change in methodology from surface to dive surveys to quantify herring spawn. Average biomass based on observed spawn was around 500 tonnes with a median around 260 tonnes, a level unlikely to sustain any directed fishery. Also, the distribution of spawn was variable among Sections and Beds in Area 9 such that resolution of stock structure was not possible based on spawn. Thus, based on the limited data currently available, it was not possible to recommend harvest opportunities be entertained at this time. With the collection of additional spawn and biosampling data future harvest might be considered in this area if population genetics confirm Area 9 herring are genetically different from the Central Coast herring population and escapement data suggests a sustainable level of biomass exists in Area 9 that could support a harvest.

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