Spatial scales of shrimp (Pandalus jordani) aggregrations, environmental influences, and consequences for management

Medium scale spatial patterns of smooth pink shrimp (Pandalus jordani) off the west coast of British Columbia exhibit periods of aggregation, and periods of dispersal. This affects catch rates by commercial vessels and affects the variance of survey estimates of abundance. Survey procedures for shrimp in this area have attempted to compensate for such changes in spatial pattern by using sector and spline interpolators over the area surveyed to estimate total abundance. Short-term availability of shrimp to commercial fishing gears is known to be influenced by environmental conditions such as tides, winds, and the amount of sunshine. In this study, we use commercial and survey data to identity spatial scales and patterns of shrimp aggregations and dispersal as influenced by environmental conditions and interannual variations in the abundance of shrimp. The goal is to improve understanding of the processes affecting the spatial distribution of shrimp so as to improve survey abundance estimates and management advice.