An analysis of the perceived impact of mussel aquaculture on catch per unit effort (CPUE) for the seasonal lobster fishery on the Northeast coast of Newfoundland

PARR-2017-NL-07

Description

Over the past two decades, lobster harvesters have noted an apparent decline in lobster catch rates on the northeast coast of Newfoundland (Lobster Fishing Areas (LFAs) 4A and 4B). This was particularly evident in the western section of Notre Dame Bay and Green Bay where mussel aquaculture is prevalent. This project used a combination of recent and historical data for lobster annual catch statistics to determine whether there is a difference in lobster landings and Catch Per Unit Effort (CPUE) in bays with active mussel aquaculture leases as compared to those without. This was the first comprehensive analysis of the interaction between lobster abundance and mussel aquaculture in the region.

Findings

Over the 10-year period (2004-2015) examined, there has been little change to the lobster mean CPUE as defined by the number of lobster to trap in LFAs 3-14C. Based on the fisher logbook data and at sea sampling data, the trends in CPUE in LFAs 4AB have remained stable since 2004.

Since the early 1990s, landings have decreased in the Northeast (LFAs 3-6) and Avalon (LFAs 7-10), and have increased in the South (LFAs 11-12) and West Coast (LFAs 13-14C) regions. The highest CPUE of lobsters was in the South Coast region, consistent with the high landings. The Northeast and Avalon regions both had low CPUE, which is consistent with the low landings.

When comparing the shellfish aquaculture production in Notre Dame Bay to the 1986 – 2016 lobster landings in LFAs 4AB, the trends showed that as shellfish aquaculture production increased the lobster landings declined in the area. However, a declining trend in landings and CPUE were also seen in LFAs where there has been no prominent shellfish aquaculture suggesting that factors other than aquaculture could have contributed to the declines.

Program Name

Program for Aquaculture Regulatory Research (PARR)

Years

2017 to 2018

Principal investigators

Harry M. Murray
Research Scientist, Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, Newfoundland and Labrador Region
Email: Harry.Murray@dfo-mpo.gc.ca

Elizabeth Coughlan
Aquatic Resources Biologist, Fisheries and Oceans Canada, Northwest Atlantic Fisheries Centre, Newfoundland and Labrador Region
Email: Elizabeth.Coughlan@dfo-mpo.gc.ca