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Wildlife of the Week!
For this round of Wildlife of the Week, we present a familiar group of amazing fishes. Hint: this group is related to scorpionfishes and stonefishes! Rockfish are a fascinating set of related species with variable characteristics and lifestyles. However, they can be more or less grouped within this common name, even in B.C. where we have such a vast number of species possible. Can you name a few common rockfish species of the Salish Sea? Read along below to learn more about rockfish.
Rockfish represent a vast number of fish, with many varieties being found in the Salish Sea; note that 34 species have been found in B.C. and nearly 28 in Puget Sound (note: likely overlapping species). To expand, there are over 96 species in the entire North Pacific. Some examples of rockfish that may be familiar are the copper rockfish (Sebastes caurinus) and the quillback rockfish (Sebastes maliger), to name only two. Rockfish can be grouped mostly into genus Sebastes, but all belong to the Family Scorpaenid, despite the group’s diversity. Depending on the species, rockfish can range in size from 12-104 cm long! Note that older rockfish will be generally larger.
The characteristics that remain consistent between the species include bony plates on the head, large circular eyes and fins that are equipped with toxins; the last trait common to all other fish in the family. These toxins vary in severity with the type of fish (i.e. stonefish are more toxic, rockfish less toxic). This means that any handling of rockfish should be done so with caution to prevent injury and infection. Rockfish also have mouths that dip downwards at the edges. Rockfish can be spiny, mottled, striped, or speckles and have achieved many color and pattern variations.
As mentioned, rockfish are found in a variety of regions, and it is difficult to generalize their lifestyles and ranges. These ranges include, as mentioned, the Pacific Ocean, as well as the Atlantic and South Pacific Oceans. Species may have different habitats, but rockfish can be seen in a diversity of habitats such as rocky reefs/crevices/caves, rockpiles, inlets, near to shore shallows, eelgrass, cobble fields, kelp forests, within the water column and even in very deep waters. Hence their namesake, “rockfish”! Despite the differences between species, rockfish are generally known to maintain a limited range in their own habitats/homes. They do not migrate.
Rockfish were an important traditional food for Indigenous Peoples living on the West Coast, and the descriptions below are not all-encompassing records. Different preparation methods for rockfish were utilized, such as boiling, barbecuing, steaming, smoking, frying and drying. For example, the Kwakwaka’wakw and the Tlingit peoples both consumed the fish fresh, and the Kwakwaka’wakw and Nuu-chah-nulth peoples were known to preserve the fish through smoking for later consumption. There were culturally important rituals and/or specific practices performed by some groups when fishing for rockfish.
Rockfish have a diverse diet, feeding on small fish (e.g. Pacific herring, surfperch, greenlings), crustaceans (e.g. crabs) and plankton. Many rockfish have a slow reproductive rate, meaning that their population growth is generally not very high year to year. In the Pacific, these fish are one of the longest lived bony fishes with some of the lowest amounts of population growth. Their low population growth is due to the fact that they do not breed until they are quite mature (at least 15-20 years, sometimes earlier beginning at 12 years) and do not produce many young. Females carry eggs after fertilization for about 4-5 weeks. The reason why preservation of older individuals is important is because older fish yield eggs with higher survival potential. The larvae produced will become a part of the pelagic plankton for one to a couple months.
In summary, rockfish mature and grow slowly, making them vulnerable to collapse. Some rockfish have been estimated to be roughly 115-205 years old.
Rockfish were an extremely valuable fish to the commercial and recreational fishing industries. This relationship has caused problems for the health of rockfish populations. Beginning around 1960 in some areas, and specifically around 1974 in Puget Sound, rockfish were more extensively fished. To describe the situation specifically in Puget Sound, this was because salmon catches were limited and rockfish thus recommended as an alternative.
Many species have witnessed limited/slow recovery even since fishing restrictions were put into place in the 1990’s. The slow recovery of the fish is attributed to many of the above-mentioned factors. The development of RCA’s (Rockfish Conservation Areas) is significant in that it restricts fishing activity and encourages awareness of the species and its threats. Other threats include barotrauma, which is the fact that due to rockfish’s swim bladders, they rarely survive catch-and-release fishing.
Some actions you can take to assist with the success of rockfish conservation include abiding by RCA’s and other restrictions, reporting the size of any rockfish catches you make and trying to choose sustainable seafood options, to name a few.
Clearly, this is a group of fish that is culturally valuable, incredibly unique and critical to a variety of ecosystems. It is also apparent that these fish need continued protection in order to continue recovering from these collapses. To learn more about rockfish, try some trivia below!
- True or False? Rockfish larvae are about the size of an eyelash. (ANS: True).
- Some populations have seen up to ___% declines since overfishing in the mid-late 1900’s (ANS: 98%).
- True or False? There are about 102 species of rockfish around the globe. (ANS: True).
BONUS CHALLENGE:
Name two predators of a rockfish.
Any two of: e.g. Harbour seal, lingcod, other fish, salmon.
Article Authored By: Alexa D., B.Sc./ Five Star Whale Watching.
To learn more about these species and/or some of the Indigenous Peoples that utilized them, visit our References below!
Department of Fisheries and Oceans Canada.
Galiano Conservancy Association.
Traditional Animal Foods of Indigenous Peoples of Northern North America.
