Fourhorn sculpin COSEWIC assessment and status report: chapter 7

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Population Sizes and Trends

Information about the size and trends of the freshwater fourhorn sculpin populations is mostly limited to presence-absence records. Most locations have not been sampled extensively or sequentially, therefore making it extremely difficult to estimate the number of individuals and the number of mature individuals in Canada. Even estimating the population size in a particular lake is difficult as abundance-level data is very limited. A couple of reasons are evident for the lack of data concerning this species:

1. The freshwater fourhorn sculpin is not harvested for commercial, recreation, or subsistence use. Though the species is considered edible, there is a small meat yield per fish and much energy and time would be required to separate the meat from the bone (Morrow 1980). This high labour-to-yield ratio makes it unfavourable as either a commercial or subsistence species. Furthermore, its small size (generally < 100 mm) causes it to be undesirable with respect to recreational fishers.
   
2. Many of the lakes the fourhorn sculpin inhabits are located in the high Arctic and far from centres of population. The isolation and inaccessibility of such water bodies thereby make it difficult to perform extensive and sequential fish population studies. The remoteness also adds cost to such studies in terms of transportation and labour. Furthermore, these lakes are generally ice-covered for most of the year because of the high latitudes in which they occur. This causes the season to be extremely short in which open-water sampling methods can be employed. Sampling through the ice is possible, but can be costly and expensive with respect to the labour and equipment required. Usually sampling only occurs when an environmental assessment is required for hydrocarbon and raw material exploration and development. Garrow Lake, for example, was only discovered in 1974 and is ice-covered for 11 months of the year. Only a few years after its discovery, the lake was used as a dumping area for waste from a lead-zinc mine to diminish the pollution input to the Arctic Ocean (Dickman and Ouellet 1987).