Science Advisory Report  2010/084

Science Advice from a Risk Assessment of Pumpkinseed (Lepomis gibbosus) in British Columbia

Summary

• Pumpkinseed is a small centrarchid, native to North America (Figure 1.), which is often kept as an aquarium fish due to its attractive colouration.
• Pumpkinseed is considered to be a nuisance species when introduced to a new region as it generates little angler interest other than as a forage fish for more highly prized piscivores.
• Pumpkinseed competes with native fish communities for habitat and food. Introduced Pumpkinseed is considered a factor in the decline of 7 out of 41 endangered fish species in Canada.
• Pumpkinseed has a high level of life history plasticity and is able to adjust its age and size at maturity as well as its diet to suit the conditions of a particular waterbody.
• Once established, factors such as later maturation and larger size at maturity allow it to be successful in a competitive environment.
• Parental care of eggs and larvae increase the chances of establishment, although, specific requirements of reproductive behaviour mean that certain environmental conditions are required for nesting to occur. A lack of suitable nest building habitat or suitable prey for larvae would decrease the chance of establishment.
• The ecological impacts, caused by the introduction of parasites and diseases associated with Pumpkinseed, were determined to be moderate with high uncertainty.
• Overall, the risk posed by Pumpkinseed ranges from moderate to high with moderate uncertainty in small waterbodies and low to high with moderate uncertainty in large waterbodies depending on the region of British Columbia considered.
• Pumpkinseed poses the lowest overall risk to the Arctic region and the highest risk to the Lower Mainland and Columbia River regions.
• Risk posed to a particular waterbody will need to be determined in a separate, specific risk assessment if required.
• Once introduced Pumpkinseed is difficult to eliminate. A proactive approach is necessary should spread be deemed undesirable.

This Science Advisory Report is from the Fisheries and Oceans Canada, Canadian Science Advisory Secretariat, regional advisory meeting of March 4-6, 2008 on Risk assessment of spiny-rayed fishes (six species). Additional publications from this process will be posted as they become available on the DFO Science Advisory Schedule.

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