Artificial Reefs Under the Scrutiny of Fisheries Protection Biologists

2017-12-21

Jacinthe Beauchamp

Since the summer of 2016, Fisheries Protection biologists have undertaken a systematic monitoring program of artificial reefs constructed in the Magdalen Islands, the Gaspé Peninsula, and on the North Shore. They conduct dives to see if the marine organisms use these reefs, and if the fauna and flora have adopted them as their habitat. In short, they want to assess and document the effectiveness and sustainability of these enhancements.

The artificial reefs are developed in particular by companies or departments that undertake projects in the marine environment. They are used to offset the serious damage caused to fish and their habitats by projects such as breakwater construction or fishing harbour expansion.

Two types of artificial reefs
For many years, two types of artificial reefs have been constructed on the seabed at depths varying from 6 to 10 metres: lobster reefs and multispecies reefs with the seeding of kelp, large-sized algae.

The lobster reefs have a 20 metre by 10 metre rectangular shape. They are composed of rocks of predetermined sizes, and are designed to ensure the success and sustainability of the enhancement. They create shelter and feeding areas for the lobster at different stages of its development. These reefs can also be colonized by a large diversity of organisms such as kelp, mussels, and small gastropods, which helps to increase the abundance of benthic fauna and fish.

For their part, multispecies reefs are pyramidal in shape and about one metre high. A few openings at the base allow crustaceans and fish to colonize. They are arranged on a seabed conducive to their deployment so as to form islands on which the algae can attach themselves. Approximately 50% of the structures are seeded with fertile kelp fronds.

Stable and sustainable reefs
To date, diving biologists have visited 10 artificial reef areas for lobster (i.e., 45 reefs of 200 m²) and 3 areas of multispecies reefs (i.e., 100 reefs of 1 m²). The success of these enhancements is indisputable. The artificial reefs are indeed colonized by a diversified fauna and flora. In addition, lobsters of all sizes have been observed in the many interstices of the reefs installed for them. Although some reefs have shown signs of instability (in particular because of silting), they are stable in the majority of cases and should be maintained for several more years.