Topic: Roundnose grenadier

Habitat

Roundnose grenadier lives in the Norwegian Trench, deeper shelf areas, and deep fjords along the Norwegian coast up to 68°N. It is mainly bottom dwelling but can be found up to 300 meters up in the water column. It is often found in large densities where it finds suitable depths.

Background

Roundnose grenadier is found on both sides of the North Atlantic; south of Iceland and along the Mid-Atlantic Ridge and the edge west of Scotland and Ireland. In our areas, it is found south of Vestfjorden, along the coast in deep shelf areas, deep fjords, and the Norwegian Trench.

Roundnose grenadier is one of two species in the Macrouridae family found in Norwegian waters; the other species is the roughhead grenadier (Macrourus berglax). The roughhead grenadier has a more northern distribution than roundnose grenadier and differs from it by having a sharper snout and even more robust and marked scales.

Deep-sea species, like roundnose grenadier, often have low production and long lifespans, making them vulnerable to impact and exploitation. Roundnose grenadier in Skagerrak can live up to 70 years, with first maturity around 7–8 years. Females spawn around 12,000–16,500 eggs that are about 1.8 mm in diameter. In comparison, an old cod can spawn up to 15 million eggs. There is also uncertainty about whether roundnose grenadier spawns every year.

Geographical distribution and recent genetic studies have defined roundnose grenadier in the Norwegian Trench/Skagerrak as a separate stock. This is further supported by differences in growth patterns between this area and other areas where roundnose grenadier is found. The fact that roundnose grenadier in Skagerrak is a separate stock makes it particularly vulnerable to exploitation.

The stock structure of roundnose grenadier northward along the Norwegian coast and into the fjords is less known, but genetic documentation shows that there are distinct populations in the fjords (Korsfjorden, Masfjorden, Lustrafjorden) and in deep coastal areas (Trondheimsleia). The population structure along the Norwegian coast appears to be determined by geographical distance and the unique bottom and depth structure of the entire area (e.g., threshold fjords) that affect dispersion and migration.

Fishing

Roundnose grenadier was previously fished in Skagerrak for both fillet and fishmeal production. In other areas, such as west of Scotland and Ireland, the fishing is mainly for fillet, and roundnose grenadier has been supplied to the French restaurant market. The fish meat is white, relatively firm, and tasty.

Fisheries

Landings of roundnose grenadier in Skagerrak have been recorded since the late 1980s. Throughout the 1990s and into the 2000s, total landings were around 2000 tons. From 2004–2005, landings increased to 11,000 tons, mainly as a result of direct fishing with increased effort. After negotiations, this direct fishery was banned from 2006. Landings of roundnose grenadier from Skagerrak have since been low, but some bycatch is recorded.

Status

The International Council for the Exploration of the Sea (ICES) provides advice on roundnose grenadier in Skagerrak (ICES area 3a) every two years. In recent years, ICES has advised against any catch of roundnose grenadier in Skagerrak. This is based on an abundance index for roundnose grenadier from the annual shrimp survey in the North Sea and Skagerrak. This index has been very low since 2012, and therefore, direct fishing for roundnose grenadier in Skagerrak is not advisable. The EU sets a quota of 2 tons for Skagerrak, which applies to bycatch; Norway does not set a quota for roundnose grenadier.