Cancer johngarthi
Encyclopedia
Cancer johngarthi is a species
of crab
that lives in the eastern Pacific Ocean
from Mexico
to Panama
. It was separated from C. porteri in 1989, and is the subject of a small-scale fishery off Baja California
.
coast of Mexico
and Central America
, from 29° N
at Isla Guadalupe
to 7° N
in Panama
, including southern parts of the Gulf of California
(Sea of Cortez).
; Garth had recorded "C. porteri" from Sinaloa
, Mexico, in 1961. It differs from C. porteri chiefly in the "paper shell" texture of the carapace. C. johngarthi also has longer legs, and stouter claws, although the differences in claws are not clear in juveniles
, due to differences in allometry. According to data from experimental fisheries, captured males varied in size from a carapace
width of 98 millimetres (3.9 in) to 176 mm (6.9 in), while females were slightly smaller, at 87 millimetre.
, initially restricted to two fishing vessel
s, with only one of the two actually engaging in fishing for C. johngarthi. The fishery consists of truncated conical crab pots, each 60 centimetres (23.6 in) tall, and tapering from 150 cm (59.1 in) at the base to 75 cm (29.5 in) at the top. They are placed 30 metre apart at depths of 100 metre. The catch per unit effort
decreases the longer the traps are left in place, and the majority of the crabs caught in the traps are male.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of crab
Crab
True crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" , or where the reduced abdomen is entirely hidden under the thorax...
that lives in the eastern Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
from Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
to Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
. It was separated from C. porteri in 1989, and is the subject of a small-scale fishery off Baja California
Baja California Peninsula
The Baja California peninsula , is a peninsula in northwestern Mexico. Its land mass separates the Pacific Ocean from the Gulf of California. The Peninsula extends from Mexicali, Baja California in the north to Cabo San Lucas, Baja California Sur in the south.The total area of the Baja California...
.
Distribution
Cancer johngarthi lives along the PacificPacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
coast of Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
, from 29° N
29th parallel north
The 29th parallel north is a circle of latitude that is 29 degrees north of the Earth's equatorial plane. It crosses Africa, Asia, the Pacific Ocean, North America and the Atlantic Ocean....
at Isla Guadalupe
Guadalupe Island
Guadalupe Island, or Isla Guadalupe is a volcanic island located 241 kilometers off the west coast of Mexico's Baja California peninsula and some 400 kilometers southwest of the city of Ensenada in Baja California state, in the Pacific Ocean...
to 7° N
7th parallel north
The 7th parallel north is a circle of latitude that is 7 degrees north of the Earth's equatorial plane. It crosses Africa, the Indian Ocean, South Asia, Southeast Asia, the Pacific Ocean, South America and the Atlantic Ocean....
in Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
, including southern parts of the Gulf of California
Gulf of California
The Gulf of California is a body of water that separates the Baja California Peninsula from the Mexican mainland...
(Sea of Cortez).
Description and taxonomic history
Cancer johngarthi was only recognised as a separate species in 1989, its members having previously been treated under C. porteri. The specific epithet commemorates John Shrader Garth of the University of Southern CaliforniaUniversity of Southern California
The University of Southern California is a private, not-for-profit, nonsectarian, research university located in Los Angeles, California, United States. USC was founded in 1880, making it California's oldest private research university...
; Garth had recorded "C. porteri" from Sinaloa
Sinaloa
Sinaloa officially Estado Libre y Soberano de Sinaloa is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 18 municipalities and its capital city is Culiacán Rosales....
, Mexico, in 1961. It differs from C. porteri chiefly in the "paper shell" texture of the carapace. C. johngarthi also has longer legs, and stouter claws, although the differences in claws are not clear in juveniles
Juvenile (organism)
A juvenile is an individual organism that has not yet reached its adult form, sexual maturity or size. Juveniles sometimes look very different from the adult form, particularly in terms of their colour...
, due to differences in allometry. According to data from experimental fisheries, captured males varied in size from a carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
width of 98 millimetres (3.9 in) to 176 mm (6.9 in), while females were slightly smaller, at 87 millimetre.
Fishery
In 2004, the government of Mexico approved a trial fishery for C. johngarthi off the Baja California peninsulaBaja California Peninsula
The Baja California peninsula , is a peninsula in northwestern Mexico. Its land mass separates the Pacific Ocean from the Gulf of California. The Peninsula extends from Mexicali, Baja California in the north to Cabo San Lucas, Baja California Sur in the south.The total area of the Baja California...
, initially restricted to two fishing vessel
Fishing vessel
A fishing vessel is a boat or ship used to catch fish in the sea, or on a lake or river. Many different kinds of vessels are used in commercial, artisanal and recreational fishing....
s, with only one of the two actually engaging in fishing for C. johngarthi. The fishery consists of truncated conical crab pots, each 60 centimetres (23.6 in) tall, and tapering from 150 cm (59.1 in) at the base to 75 cm (29.5 in) at the top. They are placed 30 metre apart at depths of 100 metre. The catch per unit effort
Catch per unit effort
In fisheries and conservation biology, the catch per unit effort is an indirect measure of the abundance of a target species. Changes in the catch per unit effort are inferred to signify changes to the target species' true abundance...
decreases the longer the traps are left in place, and the majority of the crabs caught in the traps are male.