Gobius cobitis

Researched By	Karen Riley	Data Supplied By	MarLIN
Refereed by	Prof. Robert Patzner
Taxonomy
Scientific name	Gobius cobitis	Common name	Giant goby
MCS Code	ZG463	Recent Synonyms	Gobius capito
Phylum	Chordata	Subphylum	Vertebrata
Superclass	Gnathostomata	Class	Osteichthyes
Subclass	Teleostei	Order	Perciformes
Suborder		Family	Gobiidae
Genus	Gobius	Species	cobitis
Subspecies
Additional Information	Gobius cobitis is Britain's largest goby. It inhabits high shore rock pools, often with a fresh water input. Although limited to the south west of England it is also found further afield, from the western English Channel to Morocco, the Mediterranean, the Black Sea and the Gulf of Suez.
Taxonomy References	Wheeler, 1994, Miller, 1986, Howson & Picton, 1997, Froese & Pauly, 2000(a), Pallas, 1831
General Biology
Growth form	Pisciform	Feeding method	Omnivore
Mobility/Movement	Swimmer	Environmental position	Demersal
Typical food types	Crustaceans, polychaetes, small fishes, insects and large amounts of green algae.	Habit	Free living
Bioturbator		Flexibility	High (>45 degrees)
Fragility	Intermediate	Size	Medium-large(21-50cm)
Height		Growth Rate	Insufficient information
Adult dispersal potential	No information found	Dependency	Independent
Sociability	Solitary
Toxic/Poisonous?	No
Additional Information	The feeding habits of Gobius cobitis vary with the size of the animal. Young fish, which measure about 8-9 cm, feed on smaller food items such as copepods, ostracods and small amphipods (Gibson, 1970). As the individual grows it will feed on larger food items until its diet consists of large amounts of green algae, Ulva spp., smaller amounts of crustaceans such as amphipods, crabs, prawns, amphipods, isopods and extremely small amounts of polychaetes and small fishes, particularly juveniles of the blenny, Blennius pholis (Potts & Swaby, 1992). Its longevity is approximately 10 years and the maximum total length reported was 23-27 cm (Potts & Swaby, 1992; Hayward et al., 1996). No difference in longevity has been noticed between sexes (Gibson, 1970).
Biology References	Potts & Swaby, 1992, Gibson, 1970, Hayward et al., 1996
Distribution and Habitat
Distribution in Britain & Ireland	The distribution of Gobius cobitis in Britain is restricted to the south-west coast of England, from Wembury to the Isles of Scilly.
Global distribution	Found in the eastern Atlantic, from the western English Channel to Morocco, the Mediterranean, the Black Sea (except north-west) and the Gulf of Suez.
Biogeographic range	Not researched	Depth range	Intertidal to up to 10m
Migratory	Insufficient information
Distribution Additional Information	The south-west coast of England represents the most northern limit of the giant goby's range. Gobius cobitis is common within its geographical limits. Often seen 'basking' in direct sun on exposed patches within pools. It feeds on Ulva spp., crustaceans and polychaetes. Sublittoral pools inhabited by Gobius cobitis usually contain large boulders with a crevice large enough to shelter beneath and are devoid of gravel or sand. However, Gibson (1970) recorded gravel and stones on the bottom of their rock pools and Faria et al. (1998) noted that they preferentially occupied mixed bottom and sandy substratum. Usually, there is fresh water draining into the rock pools inhabited by Gobius cobitis. Upper shore rock pools are likely to experience extremes in temperature, light levels and salinity. Despite previous records for Wembury and West Looe, Potts & Swaby (1992) found no Gobius cobitis within these areas and therefore assumed that populations had declined or were absent at that time. However, a record of Gobius cobitis was made at West Looe on 31 January 1998 by John Markham. Although there is no evidence that the species is endangered, it is potentially vulnerable to human interference due to its preferred shore habitat (Potts & Swaby, 1992). The giant goby is a very common inshore fish in the North East Atlantic and the Mediterranean (Miller, 1986).
Substratum preferences	Rockpools, Under boulders, Mixed	Physiographic preferences	Open coast
Biological zone	Sublittoral Fringe	Wave exposure	Sheltered
Tidal stream strength/Water flow	Insufficient information, See additional information	Salinity	Variable (18-40 psu)
Habitat Additional Information
Distribution References	Wheeler, 1994, Potts & Swaby, 1992, Gibson, 1970, Miller, 1986, Wheeler, 1993, Eno et al., 1997, Faria et al., 1998
Reproduction/Life History
Reproductive type	Gonochoristic	Developmental mechanism	Oviparous
Reproductive Season	Spring and summer	Reproductive Location	Insufficient information
Reproductive frequency	Annual episodic	Regeneration potential	No
Life span	See additional information	Age at reproductive maturity	1-2 years
Generation time	3-5 years	Fecundity	2,000-12,000 eggs per female
Egg/propagule size	Insufficient information	Fertilization type	External
Larvae/Juveniles Larval/Juvenile dispersal potential >10km Larval settlement period Insufficient information Duration of larval stage 11-30 days
Additional Information	The life span of Gobius cobitis is 10 years. Gobius cobitis usually mature in their second year. Females usually produce 2 clutches of eggs each season for a further 8 years (Potts & Swaby, 1992). Eggs are laid by the female and attached to the under-surface of large boulders. The eggs are fertilized and guarded by the male. Gibson (1970) suggested that males fertilise and guard batches of eggs from at least two females and that spawning occurs twice during the breeding season. Thus the eggs are protected and kept inshore until the feeding larvae hatch. The breeding season usually occurs in spring and early summer in Britain, but differences have been noted worldwide. For instance, reproduction takes place between March and May in Naples, and May to early July in Varna, the Black Sea. Fecundity was reported by Gibson (1970) to be dependent on size, and varies between 2,000 and 12,000 eggs per female. Hatching occurs approximately 22- 24 days after spawning at a temperature of 12-16 °C, and between 15 and 17 days after spawning at a temperature of 15-18 °C (Gil et al., 1997). Gobius cobitis live for approximately 10 years (Potts & Swaby, 1992; Hayward et al., 1996). No difference in longevity has been noticed between sexes (Gibson, 1970).
Reproduction References	Potts & Swaby, 1992, Gibson, 1970, Miller, 1986, Gil et al., 1997, Hayward et al., 1996