FREE ESSAY ON SCULPINS

SCULPINS

Reproduction and early life history of the Sculpin
Have you ever personally thought that fish were an interesting subject? Most people
don't. The majority of individuals consider fish ordinary, routine and insignificant.
However with a closer look, you may discover that fish can be extraordinary and extremely
significant in more ways than one. With proper education and better understanding, people
will not only realize the importance of the fish, but also the relevance of issues such
as the spawning, life history and life span of fish such as Jordania zonope (sculpins). 
Prior to the spawning season (December-January), the males move into the spawning zone in
fresh water or brackish water and are later joined by the females (Krejsa 1967;
McAllister and Lindsey 1960), [On-line]. Krejsa (1967) has reported that spawning
migration is limited to the coastal population and does not occur in the inland
population. Judging from the location of sculpin larvae taken in this study, both
migratory and nonmigratory populations exist. Spawning takes place February through June
(Krejsa 1967), [On-line]; mainly in March and April (Moyle 1976), [On-line]; February
through May (Millikan 1968), [On-line]; January through September; January through May in
Central Valley floor waters; and May through September in the foothill creeks. 
The average temperature for spawning is 8-13 C (Krejsa 1967). The saltinity is 12 ppt
(Millikan 1968); freshwater to intertidal (Moyle 1976); freshwater to oligohaline. Some
substrates are large cobbles or flat rocks (Krejsa 1967); under surface of rocks, in beer
cans, rusting automobile bodies (Millikan1968), [On-line]; trash (Moyle 1976), [On-line];
under-surfaces or crevices of rocky bottoms and banks, jetties; concrete blocks and other
artificial substrates. 
For both fresh and salt water sculpins mating activity occurs mostly at 
night or during darkened conditions. Freshwater male sculpins cleans and 
prepares a nest cavity for the female to lay her eggs; when the female lays her 
eggs she deposits them in clusters on the underside of the nest that the male has 
prepared for her. The saltwater female sculpin chases a male until she traps him 
in a crevice. She keeps him there until she lays her eggs. A mature male then 
fertilizes the eggs. A mature scalyhead sculpin has a well-developed, penis-like 
appendage that it uses to fertilize the female internally. Sculpin eggs are often 
brightly colored-green, blue, yellow, orange, pink, red - perhaps to warn off 
predators. This is a form of protective coloration among many species, which 
use bright colors to warn predators of danger. The number of eggs that are 
found in the ovary are 336-5,652 and 700-4,000 per cluster 
(Krejsa 1967); 584-10,980 eggs in ovary (Bond 1963), [On-line]; 280-7,410 
eggs in ovary (Patten 1971), [On-line]; 1,094-5,656 (Millikan 1968), [On-line]. 
Several females may lay their eggs in one males nest. The female may 
also lay eggs in more that one males nest. After the eggs are laid the male goes 
into the nest and fertilizes the eggs immediately . The male fish guards the nest 
three to four weeks or until the fry leave. He aerates the eggs by fanning them 
with his large pectoral fins until hatching occurs (Krejsa 1967), [On-line]. The 
reason the male fans the eggs is to keeps the eggs clean from bacteria and to 
keep oxygen flowing to eggs. The male also removes debris and dead eggs 
with his mouth from his nest. The father is so attentive, he may net even feed 
until the eggs hatch. Eggs adhere strongly to one another, but less to other 
substrates. 
Incubation is relatively long: 15-16 days at 12 C (Krejsa 1967), 19-20 days 
at 10-12 C (Mason and Machidori 1976), [On-line] and 14-15 days at nine to 13 C 
under laboratory conditions. Millikan (1968) noted that hatching rate of prickly 
sculpin eggs is higher at a salinity of 12 ppt than in fresh water.
A Newly fertilized egg is one point four millimeters in diameter. When the 
egg is in the stage of morula, it is one point four millimeters in diameter. The egg 
is one point five millimeters in diameter when it is at the early stage of being an 
embryo. During the late stages of being an embryo the egg is one point five 
millimeters in diameter. Most of the sculpins eggs are shaped spherically.
The yolk is orange (Krejsa 1967), [On-line]; creamy yellow-white
(Millikan 1968), [On-line]; yellowish, partially clear and partially granular. 
One large oil globule (between zero point two and zero point three millimeters in 
diameter), with many small oil globules congregating in yolk sac. The 
chorion is transparent, thick and hard. The Perivitelline space is between 
zero point one and zero point two millimeters in width. The eggs are very 
adhesiveto one another but less so to substrate. The buoyancy of the egg is 
demersal. 
Although newly hatched larvae are pelagic and are able to swim 
immediately (Krejsa 1967; Millikan 1968), [On-line]. The newly hatched prolarva 
may remain in the nest for a few hours until its body straightens out 
and it becomes free-swimming. Prickly sculpin for example do not have air 
bladders; they are usually bottom-dwellers. The very young like to swim just 
below the surface film so they can float along with the currents. In 
lakes, newly hatched sculpins swim up to the surface. It has been 
suggested that larval sculpin may use surface tension to maintain their 
position (Mason and Machidori 1976),[On-line]. Larvae remain planktonic and 
near the water surface for a period of 30-35 days 
(Krejsa 1967; Mason and Machidori 1976), [On-line]. According to Hershey 
(1985) "They are especially abundant at the surface during the darkest hours, 
moving into deeper water during the day. This allows them to feed off tiny 
plankton, which are most abundant near the surface" (p. 483). When the Larvae 
are newly hatched they are between four and seven millimeters in length. The 
yolk sac is large and spherical in the thoracic region. The oil globules are usually 
single and are located in the anterior yolk sac, with many small oil globules. At 
birth the gut is short and coiled in one loop in prolarvae but becomes twisted 
between one and two times in the prostarvae stage. Their teeth are sharp and 
pointed at birth. Size at completion of yolk-sac stage is between five point two 
and six millimeters. Preanal myomeres 8-12. Post anal myomeres are 22-26, 
the total myomeres are 32-37. The last fins to complete development are the 
pelvic fins. The pigmentation of the larvae is large stellate melanophores at base 
of pectoral fins and mid-ventral and dorsal surface of gut (near anus); a series of 
melanophores along postanal region. 
The distribution of the fish are Pelagic (Millikan 1968), [On-line]; 
planktonic or near the surface of a water column in the shallow end of the shore 
line and the deep open water of freshwater and oligohaline regions (Phinney, 
1972, p. 107). The prickly sculpin for example, range from Seward, Alaska,
southward along the Pacific Coast and into adjacent inland waters to the 
Ventura River in southern California (Barraclough, 1972, p.1922), the prickly 
sculpin have also been found to be very common in the Sacramento and San 
Joaquin rivers and estuary. Their present range may be much wider than their 
historical range, because the planktonic larvae can be distributed via the 
California Aqueduct, Friant-Kern Canal, and other man-made water transport 
systems to various portions of southern California. Evidence of the transportation 
of planktonic larvae is the population of prickly sculpin established in O'Neill 
Forebay. Sculpin larvae were among the most abundant fishes collected in 
plankton tows in Suisun Bay and the Delta from March through May. 
Juveniles become demersal at approximately 15 mm TL 
(Broadway and Moyle 1978), [On-line] and are common in shallow water with 
various bottom substrates and shelters. They may remain in upper 
estuary waters until early summer of the following year, subsequent.
Freshwater and salt water Sculpins are among the most abundant fishes 
in Alaska. On average the fresh water and salt water Sculpin matures between 
the ages of two and four years. The fresh water sculpin live in streams and lakes 
and feed on aquatic insects and salmon eggs dislodged by spawning activity. It 
also occasionally feeds on young salmon but it's predatory activity is 
insignificant. Research has found that they can live to the ripe old age of seven 
years. In comparison there is the salt water sculpin. Although they are similar in 
many ways they are also specifically distinct in many aspects. Their similarities 
between these two include some spawning habits, which are the time of year. 
The saltwater sculpins life span is not known at this time. The distinctiveness 
areas are as follows: the salt water sculpin lives in oceans or seas. When they
spawn they do not lay their eggs in a nest that has been prepared for them by the 
male. They chase the male unlike the fresh water sculpin. They have been
found in tide pools and shallow rocky coasts in Southeast Alaska to the Bering 
Sea. They have also been found over sand and to depths of 500 feet. 
In conclusions spawning, life history and life span of are extremely
important milestones in the functioning of the sculpins way of life as well as our 
own. Hopefully the subject of fish, sculpin inparticular has become one of 
interest. Information that has been shared on the subject of fresh and salt water 
sculpin wins proof that both are extremely significant as well as interesting in 
their own way. The facts that have been provided will give individuals better 
sense of understanding and further knowledge within the scope of this subject. 
References
Aplin, (1967). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Barraclough, W.E. (1972). Sculpin new to the coastal waters of BC, Journal of fisheries
research board of canada, Volume number 28, page 1922. 
Bane and Bane, (1971). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Bolin, (1944). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Phinney, D.E. (1972). Occurrence of spawning of pacific sculpin near Chignik, 
Alaska, Journal of fisheries research board of Canada, Volume number 29, page 107. 
Bond, (1963). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Broadway and Moyle, (1978). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Cook, (1964). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Eldridge, (1977). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Hershey, A.E., (1985). Diet and digestion rates of slimy sculpi, cottus cognatus in an
alaskan arctic lake. Canadian journal of fisheries and aquatic sciences, Volume number
42, page 483. 
Ganssle, (1966). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Green, (1975). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Krejsa, (1967), Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Lambert, (1979), Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Mason and Machidori, (1976). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
McAllister and Lindsey, (1960). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Messersmith, (1966). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Millikan, (1968). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Moyle, (1976). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Patten, (1971). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Richardson and Washington, (1980). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Scott and Crossman, (1973). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Stein, (1972). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Turner, (1966). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Bibliography
Bibliography 
Aplin, (1967). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Barraclough, W.E. (1972). Sculpin new to the coastal waters of BC, Journal of fisheries
research board of canada, Volume number 28, page 1922. 
Bane and Bane, (1971). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Bolin, (1944). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Phinney, D.E. (1972). Occurrence of spawning of pacific sculpin near Chignik, 
Alaska, Journal of fisheries research board of Canada, Volume number 29, page 107. 
Bond, (1963). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Broadway and Moyle, (1978). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Cook, (1964). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Eldridge, (1977). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Hershey, A.E., (1985). Diet and digestion rates of slimy sculpi, cottus cognatus in an
alaskan arctic lake. Canadian journal of fisheries and aquatic sciences, Volume number
42, page 483. 
Ganssle, (1966). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Green, (1975). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Krejsa, (1967), Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Lambert, (1979), Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Mason and Machidori, (1976). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
McAllister and Lindsey, (1960). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Messersmith, (1966). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Millikan, (1968). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Moyle, (1976). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Patten, (1971). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Richardson and Washington, (1980). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Scott and Crossman, (1973). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Stein, (1972). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)
Turner, (1966). Sculpin - Cottus asper (Richardson)
elib.cs.berkeley.edu/kopec/tr9/html/sp-prickly-sculpin.html
(30 September 2000)