Draft:Sunset Rockfish

Sunset Rockfish

The Sunset Rockfish (Sebastes crocotulus) is a species of fish found off the Southern California, and Mexican coast. It belongs to the Scopaenidae Family which consists of Rockfish and Scorpionfish. It is a cryptic sister to the Vermillion Rockfish (Sebastes miniatus), making monitoring either species difficult due to the difficulty of accurately identifying them. Only recently was the sunset rockfish classified as its own species, in 2008, previously known as Vermilion Rockfish, Type II. There is also simply a limitation of data on either of the individual cryptic sister species causing conservation efforts and attempts to understand the status of these species a struggle. Most data that is available does not distinguish between the two species, and simply states for the vermillion-sunset rockfish complex, for some details of the sunset rockfish it is generally assumed they are close enough to be the same.

Description

[edit] The coloration of the Sunset Rockfish ranges from reddish-orange to yellowish-orange. The fins are a darker shade of color than the body most of the time. They often have on the upper region of the fish have a brown spotted appearance while the vermillion’s are a darker shade of color with varying amounts of grey-spotting. They range in size up to 76cm and the largest weight was one and a half kilograms, they tend to be around half this size however. The males are typically smaller than the females. They are typically larger than their sister species. They have a small terminal mouth which they use alongside their 33 to 43 gill rakers to feed on invertebrates and small fish. Their extrinsic muscle is attached to the pectoral girdle. Both their eyes and mouths are smaller than their body size and their Vemilion counterparts. Like gill rakers, the amount of rays differ from fish to fish but they have the same amount of spines. The anal fin has 3 spines and 6 to 8 rays. The dorsal fin has 13 spines and 12 to 15 rays. The pectoral fins have 17 to 19 rays. The caudal fin is slightly lunate. Rockfish species have large ctenoid scales on their lateral line, and they have tubular scales.

Geographic Distribution

[edit] The Sunset Rockfish are off the coast of Mexico and Southern California. They live in rocky areas, hence the name rockfish, at depths from 100 meters to 840 meters. These depths are significantly deeper than the range that Vermilion Rockfish live at making them rarer to be caught by fishing and also less studied due to the increased difficulty in access to location. They school alongside several other rockfish and other fish. The sunset rockfish ranges from the approximate latitudes 37.00N to 30.00N.

The two groupings are of two subsections of sunset rockfish which is based off a genetic difference. As can be seen on the map the S-A group is found closer to the shore and at shallower depths, in addition, they are confined to further north than the S-B grouping which is found all along the coast. Reproduction and Life Cycle Sunset rockfish live long lives, are slow-growing, and have a low fecundity rate. Classifying them as a K-selected species. Due to this like most other K-selected species, they are more vulnerable. Rockfish live incredibly long lives some up to 200 years old, sunset rockfish can live to at least 60 years old. Sunset and vermillion rockfish do not have a reproductive barrier meaning they can reproduce with one another, this has lead to a multitude of subspecies groupings, 2 of groupings of sunset rockfish and 3 groupings of vermilion rockfish.. Sunset rockfish like all rockfish species are viviparous meaning the female gives birth to larvae. The female internally fertilizes her eggs after mating with a male. Some rockfish species have been known to release around 3 million larvae. The mating habits and specifics of the sunset rockfish are unknown. Feeding They feed on an array of prey, including both pelagic and benthic, such as krill, shrimp, octopus, anchovies, salps, squids, pelagic red crabs, pyrosomes, mesopelagic fishes, and other forage species.

Conservation

A big challenge in the conservation of the sunset rockfish is that a lot of data is for the vermilion-sunset rockfish complex combining the data of both species into one combined data set. The following data therefore should be understood in that context. The NOAA establishes the “first benchmark assessment” of the vermilion-sunset rockfish complex in their 2021 assessment. This data set underrepresents the sunset rockfish species as the study covers the range of latitudes from 34.27N (Point Conception) and 42.00N (California-Oregon Border), with the sunset rockfish population mostly pertaining to areas south of 34.27N. This can be seen by the map in geographic distribution. The spawning output of the vermilion-sunset rockfish complex is approximately 489 million eggs in 2021, 43% when talking about the unfished population. The management target is 40%

This chart shows that species complex spawning output has since the 2000s bounced back to the threshold of a relatively healthy amount. However, we can see the confidence interval indicates that there is a decent chance the actual spawning output is less than the management target. This uncertainty is created by the fact that this study is mostly confined to fishing activity in such natural mortality needs to be better accounted for. Especially as climate change becomes even more prominent a problem we can expect the natural mortality to change, making us more uncertain of the health of the species.

Efforts in rockfish protection such as the establishment in Southern California Bight marine reserves, Cowcod Conservation Areas (CCAs), which are just south of Point Conception. Have not been shown to be effective in conserving the sunset rockfish. In a study targeting 14 rockfish it was found that 11 were found in greater numbers inside the Cowcod Conservation Areas, the vermillion-sunset rockfish complex was not one of those species. Instead, it was found slightly at slightly higher rates outside the reservation. Meaning that these reservations have not helped the sunset rockfish most. Ongoing research in how to best monitor rockfish species such as the Sunset Rockfish include acoustical analysis which aims to be able to identify species based on distinctive noises fish make, along with more traditional methods.

Refrences

1. Aimee A. Keller, John H. Harms, Anna Elz, John R. Wallace, Jim A. Benante, Aaron Chappell, "A tale of two species: Vermilion and sunset rockfish in the Southern California Bight", Fisheries Research, Volume 250, 2022, https://doi.org/10.1016/j.fishres.2022.106275
2. Keller, Aimee A., et al. “Changes in Long-Lived Rockfishes after More than a Decade of Protection within California’s Largest Marine Reserve.” Marine Ecology Progress Series, vol. 623, 2019, pp. 175–93. JSTOR, https://www.jstor.org/stable/26789881. Accessed 19 Oct. 2024.
3. Longo, G.C., Harms, J., Hyde, J.R. et al. "Genome-wide markers reveal differentiation between and within the cryptic sister species, sunset and vermilion rockfish." Conserv Genet 23, 75–89 (2022). https://doi.org/10.1007/s10592-021-01397-4
4. Monk, Melissa H.;Dick, E.J.;Field, John C.;Saas, Emma M.;Rogers, Tanya L., "The status of Vermilion Rockfish (Sebastes miniatus) and Sunset Rockfish (Sebastes crocotulus) in U.S. waters off the coast of California north of Point Conception in 2021", Pacific Fisheries Management Council, 2021 https://repository.library.noaa.gov/view/noaa/45277
5. Phillips, J.B. 1964. "Life history studies on ten species of rockfish (genus Sebastodes)". Fish Bulletin 126.
6. Rankin, Polly S., et al. “Effect of Hypoxia on Rockfish Movements: Implications for Understanding the Roles of Temperature, Toxins and Site Fidelity.” Marine Ecology Progress Series, vol. 492, 2013, pp. 223–34. JSTOR, https://www.jstor.org/stable/24892790. Accessed 19 Oct. 2024.
7. Širović, Ana, and David A. Demer. “Sounds of Captive Rockfishes.” Copeia, vol. 2009, no. 3, 2009, pp. 502–09. JSTOR, http://www.jstor.org/stable/25622933. Accessed 19 Oct. 2024.
8. Snow, John, "Sunset Rockfish", MexicanFish.com, https://mexican-fish.com/sunset-rockfish/#:~:text=The%20Sunset%20Rockfish%20is%20a,females%20being%20larger%20than%20males Accessed 13 Nov, 2024