Citharichthys stigmaeus

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Citharichthys stigmaeus
Citharichthys stigmaeus (Speckled Sanddab).jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Carangiformes
Family: Paralichthyidae
Genus: Citharichthys
Species:
C. stigmaeus
Binomial name
Citharichthys stigmaeus

Citharichthys stigmaeus, the speckled sanddab, is a species of lefteye Blothid flounder in the genus Citharichthys . [1] It is native to the eastern Pacific Ocean, ranging from Alaska in the north to Baja California, Mexico in the south. It is usually found in benthic habitats, in both bays and coastal areas. It varies temporarily both seasonally and annually. It is often found highest in abundance during the spring and summer (due to a large number of juveniles), but are found in much lower densities in the winter. [2]

Contents

Geographic distribution of the speckled sanddab along the California coast. Geographic distribution of the speckled sanddab along the California coast.png
Geographic distribution of the speckled sanddab along the California coast.

While the Speckled sanddab is technically a game fish, it is of little commercial importance due to its diminutive size, and the larger Pacific sanddab is readily available. The species has a high rate of reproduction, and coupled with the minimal threat from fishing means that it is abundant along the entire North American coast. Over the past few decades, due to its abundance, it has been used in various studies throughout the coast to analyse benthic species distribution and feeding habits. [3]

Description

It is a much smaller cousin of the Pacific sanddab (C. sordidus), growing to a maximum of 17 centimetres (6.7 in) in length. It can be found on the sandy bottom near the shore to as far out as 350 metres (1,150 ft). It is a dull brown or tan colour, with a white or pale brown underside. Males are often mottled with orange spots. It is not to be mistaken with the English sole, which also has similar appearance due to its compressed body form and similar body proportions (including caudal lengths). [1] The main difference between the Speckled sanddab and the English sole lies in their mouth and jaw structures, which also causes them to have slightly varied diets. [1] The Speckled sanddab has both eyes on the left side of its body, with symmetrical jaws and asymmetrical pelvic fins. [4] The Pacific sanddab can be distinguished from other similar Citharichthys species, the Speckled sanddab does not develop rays during its developmental stages. [5]

Life history

The Speckled sanddab animalia kingdom, the phylum chordata and part of the actinopterygii class. [6] The morphology of the Speckled sanddab is thought to have originated from one common ancestor as a part of a monophyletic group, but the development of the same-side eye placement has been contested over time. In 2008, a study rediscovered two intermediate species, Amphistium paradoxum and Heteronectes chaneti, which were previously neglected. These species had eyes that had migrated upwards, proving that the evolution of the same-sided eyes was a gradual evolutionary shift, rather than a single event. [7]

Larval Development of the Speckled sanddab (Ahlstrom and Moser 1975) Larval Development of the Speckled sanddab (Ahlstrom and Moser 1975).png
Larval Development of the Speckled sanddab (Ahlstrom and Moser 1975)

Juveniles are largely found in shallow, coastal, sandy habitats for the spring and summer of their first year (first growth season). [8] They utilise both coasts and bays as nursery habitats. Although they are mostly found relatively close to the coast, they do not necessarily depend on shallow waters for nursing grounds, as they can also be found in deep channels. [2] Citharichthys lay eggs that are spherical and contain oil globules that develop from singular to several over the course of maturity. [5] Juveniles mature rapidly and have a short pelagic stage. They reach maturity at a generally smaller body size than many other flatfish, which is advantageous for nursing in more tumultuous coastal environments. At the end of the first growth season, juveniles move further offshore to join the adult population in more offshore pelagic habitats. [8]

Ecology and behaviour

One of the main defensive mechanisms the species has is that it can camouflage itself by adapting to look like the surface it is on. This allows the species to avoid being seen in murkier benthic environments by blending in with the surrounding sediment. It has various anti-predator responses, mostly evasive, and tends to be more reserved with predation and feeding when there are predators present. It varies its posture and movement depending on the presence or absence of food and predator cues. [9]

The Speckled sanddab may be one of the more resilient flatfish species, as one study conducted in 2017 exposed it to varying levels of CO₂ and assessed their responses accordingly. It showed potential resilience to CO₂ and may be generally better equipped to tackle ocean acidification. However, it was found that after exposure to high levels of CO₂, it was slower to demonstrate successful feeding habits. [9] Other studies have also been conducted to show that the Speckled sanddab may be more sensitive than other California fish species to marine habitats with increased sulfide concentrations, as they are unable to effectively detoxify sulfide through oxidation, which may reflect a smaller environmental niche. [10]

Well-hidden speckled sanddabs at the Steinhart Aquarium Speckled Sanddabs CAS 1.JPG
Well-hidden speckled sanddabs at the Steinhart Aquarium

Diet

The Speckled sanddab feeds on both epibenthic and benthic organisms throughout the water column. It’s mouth is equipped with a moderate mouth, long symmetrical jaw, sharp teeth and serrated gill rakers in order to aid the mechanical breakdown of prey. [4] It eats small crustaceans, polychaetes, bivalve siphons, copopods, mysids, caprellids, cumaceans, shrimp, crab and other smaller fish. [9] Its predators are various fish, birds and marine mammals. A study done in 1965 found that halibut were responsible for around 78% of monthly Speckled sanddab mortalities in the San Diego County. [2] As the species grows larger in size, it is able to diversify its diet further and consume a larger variety of prey. [1]

Conservation status

The Speckled sanddab has experienced various ecological and anthropogenic threats over the past few decades. In the 1980s, sanddabs experienced increased parasitism, infection and mortality rates, due to factors like water temperature fluctuation, pollution and human interference. [4] Over time, its conservation status has shifted due to variations in external threats. In 2020, the International Union for Conservation of Nature declared it as ‘Least Concern’ status as it is both not endangered, harmless to humans, and only minorly used for commercial purposes. [6] Although the species in itself is not necessarily endangered, biogeographical shifts to the coastline are occurring due to climate change, which may alter the composition of habitats like estuaries and bays. As these coastal shifts continue to occur, the Speckled sanddab may struggle to find sufficient nursing grounds for development and protection, putting the population at risk.

Related Research Articles

<i>Citharichthys</i> Genus of fishes

Citharichthys is a genus of flatfish in the large-tooth flounder family, Paralichthyidae. They have both eyes on the left sides of their heads. They are native to the oceans around the Americas, with a single species, C. stampflii off the West African coast. Most are found in relatively shallow depths, but the genus also includes species found in deep water and species that enter fresh water.

<span class="mw-page-title-main">Scophthalmidae</span> Family of fishes

The Scophthalmidae are a family of flatfish found in the North Atlantic Ocean, Baltic Sea, Mediterranean Sea, and Black Sea. Fish of this family are known commonly as turbots, though this name can refer specifically to Scophthalmus maximus, as well. Some common names found in species of this family are turbots, windowpanes, and brills.

<span class="mw-page-title-main">Pelagic fish</span> Fish in the pelagic zone of ocean waters

Pelagic fish live in the pelagic zone of ocean or lake waters—being neither close to the bottom nor near the shore—in contrast with demersal fish that live on or near the bottom, and reef fish that are associated with coral reefs.

<span class="mw-page-title-main">Demersal fish</span> Fish that live and feed on or near the bottom of seas or lakes

Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes. They occupy the sea floors and lake beds, which usually consist of mud, sand, gravel or rocks. In coastal waters, they are found on or near the continental shelf, and in deep waters, they are found on or near the continental slope or along the continental rise. They are not generally found in the deepest waters, such as abyssal depths or on the abyssal plain, but they can be found around seamounts and islands. The word demersal comes from the Latin demergere, which means to sink.

<span class="mw-page-title-main">California halibut</span> Species of fish

The California halibut or California flounder is a large-tooth flounder native to the waters of the Pacific Coast of North America from the Quillayute River in Washington to Magdalena Bay in Baja California.

<span class="mw-page-title-main">California sheephead</span> Species of fish

The California sheephead is a species of wrasse native to the eastern Pacific Ocean. Its range is from Monterey Bay, California, to the Gulf of California, Mexico. It can live for up to 20 years in favorable conditions and can reach a size of up to 91 cm (3 ft) and a weight of 16 kg (35 lb). It is carnivorous, living in rocky reef and kelp bed habitats, feeding primarily on sea urchins, molluscs, and crustaceans.

<span class="mw-page-title-main">Mad River (California)</span> River in California, United States

The Mad River is a river in upper Northern California. It flows for 113 miles (182 km) in a roughly northwest direction through Trinity County and then Humboldt County, draining a 497-square-mile (1,290 km2) watershed into the Pacific Ocean north of the town of Arcata near [California Redwood Coast-Humboldt County Airport] in McKinleyville. The river's headwaters are in the Coast Range near South Kelsey Ridge.

<span class="mw-page-title-main">Yellowbelly flounder</span> Species of fish

The yellowbelly flounder is a flatfish of the genus Rhombosolea, found around New Zealand. A different species from the genus Rhombosolea is found in Australia and also goes by the name yellow-belly flounder. The Māori people have commonly fished for R. leporina, and many other species of flatfish, throughout New Zealand's coastal waters for hundreds of years. The Māori name for this species is pātiki tōtara.

<span class="mw-page-title-main">Pacific sanddab</span> Species of fish

The Pacific sanddab, also known as the soft flounder, mottle sanddab, or megrim, is a fish species in the order Pleuronectiformes, or flatfish. It is by far the most common sanddab, and it shares its habitat with the longfin sanddab and the speckled sanddab. The adult Pacific sanddab is bilaterally asymmetrical and ‘left-eyed’, meaning both eyes are located on the left side of its body.

<i>Paralabrax clathratus</i> Species of fish

Paralabrax clathratus, the kelp bass, bull bass or calico bass, is a species of marine ray-finned fish, from the subfamily Serraninae, classified as part of the family Serranidae which includes the groupers and anthias. It is found in the eastern North Pacific Ocean where it is an important species for both recreational and commercial fisheries.

<span class="mw-page-title-main">Ecology of the San Francisco Estuary</span>

The San Francisco Estuary together with the Sacramento–San Joaquin River Delta represents a highly altered ecosystem. The region has been heavily re-engineered to accommodate the needs of water delivery, shipping, agriculture, and most recently, suburban development. These needs have wrought direct changes in the movement of water and the nature of the landscape, and indirect changes from the introduction of non-native species. New species have altered the architecture of the food web as surely as levees have altered the landscape of islands and channels that form the complex system known as the Delta.

<span class="mw-page-title-main">Greater amberjack</span> Species of fish

The greater amberjack, also known as the allied kingfish, great amberfish, greater yellowtail, jenny lind, Sea donkey, purplish amberjack, reef donkey, rock salmon, sailors choice, yellowtail, and yellow trevally, is a species of predatory ray-finned fish in the family Carangidae, the jacks and pompanos. It is found in temperate, subtropical, and tropical seas around the world. It is a popular quarry species for recreational fisheries and is important in commercial fisheries. It is the largest species in the family Carangidae.

<span class="mw-page-title-main">Stout whiting</span> Species of fish

The stout whiting, also known as the yellow-cheek whiting or school whiting, is a species of benthic marine fish in the smelt-whiting family Sillaginidae. Like other sillaginids, it is an elongate, slightly compressed fish, growing to a maximum known length of 30 cm. The stout whiting is endemic to Australia, with the species divided into western and eastern populations, with the western population ranging from Shark Bay to Fremantle and the eastern population from Bustard Head, Queensland to northern New South Wales. The species inhabits deep, sandy continental shelf regions to a depth of at least 70 m.

<span class="mw-page-title-main">Coastal fish</span> Fish that inhabit the sea between the shoreline and the edge of the continental shelf

Coastal fish, also called inshore fish or neritic fish, inhabit the sea between the shoreline and the edge of the continental shelf. Since the continental shelf is usually less than 200 metres (660 ft) deep, it follows that pelagic coastal fish are generally epipelagic fish, inhabiting the sunlit epipelagic zone. Coastal fish can be contrasted with oceanic fish or offshore fish, which inhabit the deep seas beyond the continental shelves.

Citharichthys gilberti, the bigmouth sanddab, is a species of flatfish in the large-tooth flounder family Paralichthyidae. It is native to the eastern Pacific Ocean, in tropical waters ranging from the Gulf of California in the north to Peru in the south. It occurs in shallow waters off the coast, to a maximum depth of 36 m (118 ft).

Citharichthys mariajorisae, the five-rayed sanddab, is a species of flatfish in the large-tooth flounder family Paralichthyidae. It is native to the eastern Pacific Ocean, in tropical waters ranging from the Gulf of California in the north to the Bay of Panama in the south. It is a demersal marine fish, inhabiting the sandy bottoms of shallow coastal waters at a depth between 10 and 45 metres.

Citharichthys xanthostigma, the longfin sanddab, is a species of flatfish in the large-tooth flounder family Paralichthyidae. It is native to the eastern Pacific Ocean, in subtropical waters ranging from Monterey Bay, California in the north, to Costa Rica in the south. It is a demersal marine fish, and can be found on the soft bottoms of coastal waters at depths between 2 and 201 metres.

<span class="mw-page-title-main">Gulf flounder</span> Species of fish

The Gulf flounder is a species of saltwater flounder.

<i>Zebrias</i> Genus of fishes

Zebrias is a genus of ray-finned fish in the family Soleidae.

<span class="mw-page-title-main">Bay whiff</span> Species of fish

The bay whiff is part of the family Paralichthyidae. This family is known as "left-eye flounders". They are one of the most common flatfish of the Gulf of Mexico. They are benthic ambush predators with the ability to camouflage themselves on or just below the surface. They are often solitary animals with few individuals. They vary in color from light to dark in life and are brownish in color after death. They have two dark spots on the caudal peduncle and a light spot under the pectoral fin. The average size of the Bay whiff is 15 cm and the maximum recorded length is 20 cm. The lateral line is straight along the body. It has a large mouth. The opercle on the blind side has no cirri. Their pelvic fins are also asymmetrical.

References

  1. 1 2 3 4 Brezina, John (1979). Feeding studies on three species of fish from Tomales Bay, California (Thesis) via University of the Pacific Thesis and Dissertations.
  2. 1 2 3 Hendrix Kramer, Sharon (1991). THE SHALLOW-WATER FLATFISHES OF SAN DIEGO COUNTY (PDF) (Report). CalCOFl Reports. Vol. 32. Southwest Fisheries Science Center National Marine Fisheries Service, NOAA.
  3. Emmett, Robert L.; Hinton, Susan A. (September 1992). "Benthic and Epibenthic Invertebrates, Demersal Fishes, and Sediment Structure off Tillamook Bay, Oregon, September 1990, with Comparisons to Previous Surveys" (PDF). Coastal Zone and Estuarian Studies.
  4. 1 2 3 Rackowski, Joseph P.; Pikitch, Ellen K. (August 1989). Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (Pacific Southwest), Pacific and Speckled Sanddabs (PDF) (Report). Coastal Ecology Group and Wildlife Service.
  5. 1 2 California Cooperative Oceanic Fisheries Investigations (PDF) (Report). CalCOFI Atlas Series. State of California Marine Research Committee. June 1975. Atlas No. 22.
  6. 1 2 Munroe, T.A. "Citharichthys stigmaeus". The IUCN Red List of Threatened Species 2021. IUCN. Retrieved 14 November 2024.
  7. Friedman, Matt (July 10, 2008). "The evolutionary origin of flatfish asymmetry". Nature. 454 (7201): 209–212. Bibcode:2008Natur.454..209F. doi:10.1038/nature07108. PMID   18615083.
  8. 1 2 Brown, Jennifer A.; et al. (27 December 2005). "Classification of Juvenile Flatfishes to Estuarine and Coastal Habitats Based on the Elemental Composition of Otoliths". Estuarine, Coastal and Shelf Science, Academic Press.
  9. 1 2 3 Andrade, J (2017). "Effects of Elevated CO₂ on Speckled Sanddab (Citharichthys stigmaeus) Behavior". Oregon State University.
  10. Bagarinao, T; Vetter, R.D. (December 1990). "Oxidative detoxification of sulfide by mitochondria of the California killifish Fundulus parvipinnis and the speckled sanddab Citharichthys sitgmaeus". J Comp Physiol B. 160 (5): 519–527. doi:10.1007/BF00258979.