hydroacoustic and midwater trawl segment of the rockfish survey) Ma­ Shortbelly Rockfish, Sebastes jordan;: l son ). A Large Unfished Resource in Preparation of this paper was Waters Off California prompted by the interest shown by both fishermen and processors in developing a fishery for shortbelly rockfish. The WILLIAM H. LENARZ objectives of the paper are to sum­ marize information on the species and: I) Describe the biology of the species, 2) make first approximations of the reaction of the stock(s) to various levels Introduction objects such as reefs or kelp more often of fishing, 3) review the rockfish survey than most, if not all, Cal ifornia rep­ results with regard to fishing, 4) review The shortbelly rockfish, Sebastes resentatives of the genus. Occasional potential of a fishery, and 5) discuss jordani, is one of the more distinctive catches have been made by purse sein­ management options for the fishery. members of the 57 species of rockfish ers fishing in southern California wa­ (genus Sebastes) which are reported ters, and the species predominated in Biology from California waters. The species ob­ midwater and demersal trawl catches of tains its common name from the fact rockfish off central California in the Larval and Juvenile Stages that its vent is about midway between 1977 rockfish survey (Gunderson and Moser et al. (1977) summarized the origin of the anal fi n and insertion of Sample, 1980). available information on larval and the pelvic fin, while the vent of other Shortbelly rockfish have been re­ juvenile stages of shortbelly rockfish. species of rockfish is located farther ported from San Benito Island, Baja The larvae are released at an average back, much closer to the origin of the California, Mexico (Moser et aI., 1977) size of 5.4 mm by the ovoviviparous anal fin. The shortbelly rockfish also to La Perouse Bank, British Columbia females between January and April. has a more strongly incised tail and a (Miller and Lea, 1972). Miller and Lea Larvae were collected between north­ more fusiform shape than most also report maximum depth as 283 m ern Baja California, Mexico, and as far rockfish. (155 fathoms) and maximum total north as San Francisco, Calif. Their Moser et al. (1977) noted that larvae length as 305 mm (12 inches). samples were not taken north of San of shortbelly rockfish are the longest at While there is no fishery for Francisco. While larvae were collected birth of eastern Pacific rockfish studied shortbelly rockfish, the species appears as far as 278 km (150 miles) offshore, to date. Also, the larval period is long to be very abundant in California wa­ all above-average catches were taken prior to transformation to the juvenile ters. Moser et al. (1977) estimated that much closer to shore. They also re­ stage when compared with other east­ larvae of shortbelly rockfish composed ported that larvae metamorphose to ern Pacific rockfish. These features, in 20 percent of all rockfish larvae taken in juveniles at 27 mm and appear to begin addition to the pigmentation pattern and a sampling program off southern forming schools at the surface at that morphometrics of young larvae, are California and 12 percent off central time. Juveniles up to 62.8 mm have remarkably similar to those of the California in 1966. While the catch of been taken by dip nets under night redfish or ocean perch, S. marinus, shortbelly larvae compared with all lights. On the other hand, specimens as group of the Atlantic Ocean. rockfish larvae was higher off southern small as 70 mm were taken by bottom Another distinction of adult California than central California, the trawling during the rockfish survey. shortbelly rockfish is that it occurs in catch per standard haul was higher off midwater and away from underwater central California (4.22 larvae) than Growth southern California (2.65 larvae). The Shortbelly rockfish, while being one biomass in a limited area of its range, of the smaller species of rockfish, has William H. Lenarz is with the Tiburon Labora­ between Pt. Ano Nuevo and Pt. San the highest rate of growth completion tory, Southwest Fisheries Center, National Marine Fisheries Service, NOAA, 3150 Paradise Pedro, was estimated to be 295,000 (k) of 10 California species studied by Drive, Tiburon, CA 94920. metric tons (t) from the results of the Phillips (1964). The von Bertalanffy

ABSTRACT-Shortbellyrockfish, Sebas­ imations ofthe effect offishing on the stock, 'Mason, 1. E. 1978. Preliminary report on the tes jordani, appear to be abundant in 3) a review of the rockfish survey results hydroacoustic/midwater trawl survey for rockfish conducted off parts of the American and Cana­ to 4) California waters and present the potential with regard fishing, a review of the dian west coasts during July 12-September 30, for development ofa new largefishery in the potential for development of a fishery, and 1977. Unpubl. manuscr., 6 p. Northwest and area. This paper contains: 1) A description 5) a discussion of management options for Alaska Fisheries Center, NMFS, NOAA, 2725 ofthe biology ofthe species, 2)first approx- the fishery. Montlake Blvd. E., Seattle, WA 98112.

34 Marine Fisheries Review growth curve was used to describe fish from several sources and evalua­ growth: tion of selectivity is not possible. Data Females from the surveys (Fig. 2) indicated that = -k(f-f ») L f L x(l-e O 28 females grow larger than males and at­ Moles tain maximum size at a slower rate of where L f = total length (mm) at t, 24 completion (lower k). Growth does not t = age in years, appear to be related to depth ofcapture,

k = growth completion 20 but there are insufficient data from the rate, survey to arrive at conclusive results. to= theoretical age when Length-Weight fish is length 0, and The length-weight relationship was Lx = estimate of average estimated by Phillips to be log W = length attained at a +{3logL, where W = weight in maximum age. pounds, L = total length (mm), a = -8.05202, and {3 = 3.1518. Phillips combined age-length data from Maturation, Fecundity, and both sexes and made his estimates from 1 2 3 " 5 6 7 8 9 10 Sex Composition back-calculated lengths (estimates of Age (yeors) length at time of formation of each an­ Phillips (1964) reported that 50 per­ nual ring on a scale) made from scale cent of shortbelly rockfish "... are Figure I.-Von Bertalanffy growth readings and measurements. He as­ mature when 6Jh inches [16.5 cm] curves for Sebastesjordani estimated long, or 3 years old." The fecundity­ sumed that scales form at birth. My from this study and by Phillips experience with several other species of (1964). length relationship, estimated by me rockfish indicates that scales form when from Phillips' data on to specimens is the fish reach about 20 mm. Thus the In F = a + /3lnL, where F = fecundity back-calculations of Phillips probably (numbers of eggs), L = total length slightly under-estimate lengths of (mm), a = -8.43523, and f3 = 32 young fish. 3.30611. Additional data on growth are avail­ About 45 percent of the survey 2. able from the rockfish survey. Otoliths catches of shortbelly rockfish between from 1,081 specimens were read. 14 cm and 27 cm were males. Few of Opaque zones of fast growth were just 2' the fish larger than 27 cm were males. beginning to be formed at the time of 20 Movements sampling (midsummer). Phillips' ~ back-calculations appear to be at the .c While many aspects of the life his­ '"e I. end of the growth season (midwinter). ~ tory of shortbelly rockfish appear in the ;; Thus fish from the rockfish survey ~ literature, nothing could be found on should be 0.5 year older than those Phil­ 12 movements. Tagging studies on blue lips used. Phillips used total lengths, rockfish, S. mystinus, Miller and while fork lengths were measured for Geibel (1973); yellowtail rockfish, S. the rockfish survey. Total length is flavidus, Carlson and Haight (1972); about 15 mm greater than fork length copper rockfish, S. caurinus, Dewees for shortbelly rockfish, and the survey (1970); and black-and-yellow rockfish, data were adjusted accordingly. The Pacific ocean perch, S.

March-April 1980 35 alutus, indicate considerable move­ ment into relatively shallow waters dur­ ~228m ing spring and summer and return to LN.44'59'N deeper water in the winter (Gunderson, '::UL C C 1972). Pacific ocean perch have more strongly indented tails and fusiform WOOL ~N'39'59'N bodies than the five species that were 500 tagged but less than shortbelly rockfish. 0 LLrr Sorokin (1961) documented long (at 4000L least I ,112-krn (600-mile» migrations 2000 LN.3B'59'N of stocks of redfish (or ocean perch), 0 LfuL and deep-water redfi sh, S. mentella, in £ the Atlantic Ocean. '" 2o.000L '0 LillN.37' 59'N Data from bottom trawl catches of :u 10.000 .0 the rockfish survey indicate that E 0 lOLL :> shortbelly rockfish do make significant Z 40.00° movements. Length and age samples 20,000 LN'36'59'N were expanded to entire catches assum­ ing that sampled fish were taken at ran­ 0lnL LL dom. Size offish tends to increase with 400° depth (Fig. 3). Size for a given depth 2000 LN.35'59'N stratum tends to increase in a northerly 0bnL LL direction between lat. 34° and 39° N. Depth of capture of shortbelly rockfish 2000UlL1000 LN'34'59'N also tends to increase in a northerly L~ direction between lat. 35° and 39° N. 0 20 30 10 20 30 10 20 30 10 20 30 The combined results of these trends is '0 Fork length (em) a very strong tendency for size to in­ crease in a northerly direction between Figure 3 .-Length composition ofSebastes jordani caught by bot­ lat. 34° and 39°N (Fig. 4). While age tom trawling during rockfish survey as a function of depth and composition data are not sufficient to latitude. separate effects of depth and latitude, age of shortbelly rockfish tends to in­ o 44° N·44° !)9"N crease as depth and latitude increase (Fig. 5). The age and length composi­ ~J9'N-39"S9'N tion data from the rockfish survey indi­ 37° lS'N ~rv- L-L-J~ 38"N·JS'S9'N cate that at least during summer, 2o'OOOh10.000 144m shortbelly rockfish tend to move into o ~-~~-~~~ 10.~[ II h37'N.370S9·N deeper waters and to the north as they ,OOO~ 2O.~[ 37" S'N grow. c=O 36° N-36°S9'N 200: 176m Data on larvae revealed areas of heavy spawning from Los Angeles to at ~[ c=[]~~ least San Francisco during January JO.OO°lrll20,000 36° 59'N 114m 1966 and March 1975. 2 Very heavy ~~"N 10,000 '----~-~--~~ spawning occurred off Monterey (lat. 10 15 20 ~ ~ ~ o 37°N), Avila Beach (lat. 35°N), and Fork lengfh (em) 35° 4S'N Santa Barbara (lat. 34ON). Heaviest '~~ 95m Figure 4.-Length composition of spawning occurred off Monterey. The Sebastes jordani caught by bollom I 2 --:3=--,.,---'-75 -'-:',-'-:'-'-:.,..-'-9:::-'--,""0-"--:";-''' heavy spawning from Los Angeles to at trawling during rockfish survey as a Age (yeors) least San Francisco in the same month function of latitude. Figure 5.-Age composition of bot­ indicated that if shortbelly rockfish do tom trawl catches ofSebastes jordani tend to move north as they grow, they during rockfish survey. do not make long return migrations to the south in the winter to spawn. Relationships With Other Species Shortbelly rockfish appear to be an 2Unpublished data of H. G. Moser, Southwest Fisheries Center, NMFS, NOAA, P.O. Box 271, important prey item in central and found that rockfish represented 22.5 La Jolla, CA 92038. Pers. commun. 1978. southern California. Merkel (1957) percent of the food volume of chinook

36 Marine Fisheries Review 20 20 ::l Sebosles jordoni o ' , , , ,,,,, ,, !,, 16 16 L E 25 .s 20 ~ § .c E V> 12 12 '5 Sebosles goodei '0. 1 ~ '0 0. ~ '" i ~ .0 5 ~ '0 ~ 8 .c 8 0 -rrf l "0 z .c c 1> '"~ 20 C ...J ~ 15 Sebasles poucispinis '" ',r 0 rh a b 26 26 30 32 34 36 38 '0 50 0 40 60 20 40 60 Number of gill rakers" " " " 20 Fork length (em) Figure 6.-Gill raker frequencies of Sebastes jordani, S. goodei, and S. Figure 7. - Relationshi ps between length of paucispinis. longest gill raker and fork length (a) and length of upper jaw and fork length (b) for Sebastes jordani, S. goodei, and S. paucispinis. salmon, Oncorhynchus tshawytscha, undetermined portions of the diets of suggest that shortbelly rockfish con­ off San Francisco between February some birds. Only two studies reported sume the smallest organisms, probably and November. In June and July more the size of consumed shortbelly plankton, of the three species and than 50 percent of the food was rockfish. In both cases small fish, prob­ bocaccio consume the largest, probably rockfish, of which 70 percent was ably less than 1 year old, predominated. fish. Phillips (1964) stated that the shortbelly rockfish. Few of the rockfish Shortbelly rockfish belong to a group shortbelly rockfish " ... feed exclu­ exceeded 89 mm (3.5 inches). Short­ of important rockfish that inhabit sively on macroplanktonic organisms, belly rockfish less than 89 mID are California waters between 50 and 125 primarily euphausids," while chilipep­ probably in their first year of life. Of78 fathoms (91 and 229 m) during adult per" ... may feed on euphausids and fish sampled from pigeon guillemots, life. The other two members are bocac­ small squids, or on small fishes such as Cephus columbia, nesting on the Faral­ cio and chilipepper, both of which are anchovies, young hake, Merluccius Ion Islands, two were shortbelly very important components of Califor­ productus, and lanternfish," and rockfish that were 59 and 83 mm in nia rockfish landings. All three species bocaccio " ... feed on smaller standard length (Follet and Ainley, are relatively fusiform and have deeply rockfishes, sablefish, Anoplopoma 1976). Hubbs et al. (1970) reported that incised tails for rockfish. fimbria, anchovies, lantern-fish, and 4 otoliths of shortbelly rockfish were Since the three species are often squids, Loligo opalescens." found in 498 otoliths sampled from caught together and belong to the same A compilation of upper jaw length western gull, Larus occidentalis, cast­ genus, ecological theory requires that frequencies of the three species in ings near San Diego. The fish were there be mechanisms that separate the rockfish survey tows containing thought to have been stolen from species into different niches. Mor­ shortbelly rockfish indicates little over­ Brandt's cormorant, Phalacrocorax phological features, measured follow­ lap (Fig. 8). Since young specimens of penicillatus. Trawl-caught bocaccio, ing procedures of Phillips (1957), re­ the larger species have jaw lengths of S. paucispinis, and chilipepper, S. lated to feeding differ considerably the same size as older specimens of the goodei, are often seen with shortbelly among the species. For example, there smaller species, the lack of overlap rockfish protruding from their mouths, is almost no overlap in gill raker counts shown in Figure 8 suggests that the but these specimens may represent un­ for the three species (Fig. 6). However, three species are distributed in a fashion natural feeding within the trawl. A the relationship between length of the that minimizes the possibility of com­ number of studies on food of fish, largest gill raker of the first arch and petition for food. marine mammals, and birds found fork length is similar for chilipepper small rockfish to be important prey and shortbelly rockfish, but differs be­ First Approximation of items, but did not identify the items to tween these two species and bocaccio Reaction of Species to Fishing species. In summary, at times (Fig. 7a). There are considerable dif­ Yield per recruit calculations often shortbelly rockfish can be an important ferences in the relative length of upper are used to make first approximations of prey item for chinook salmon and pos­ jaw among the species (Fig. 7b). The production of a stock under different sibly other fish. They also compose yet data presented in Figures 6 and 7 fishing strategies. Estimates of growth

March-April 1980 37 06 05

04 :2 '" "0 ~ J:J ~Sebasles gaadei E z~ a b '"0 J --' 0.1 0.2 0.3 0,4 0.1 0,2 0.3 0.4 Sebasles pauclsplnis Fishing mortality Figure 9.-Yield per recruit (a) and relative fecundity (b) (production of larvae by fished stock/production of lar­ vae by unfished stock) ofSebastes jordani as functions of Length of upper jOW(CM) age at recruitment and instantaneous rate of fishing mor­ tality (F). Figure 8.-Frequencies of upper jaw length of Sebastes jordani. S. goodei. and S. paucispinis caught in The fecundity of shortbelly rockfish ing 1976 (Table I). An area of high rockfish survey bottom trawls con­ taining S. jordani. is similar to the clupeids which have a catches by both gears in both years was well-documented history of recruit­ between lat. 36°56' and 3r21'N. ment failures in heavily fished stocks Large catches were made by both gears and mortality are needed for the calcu­ (Murphy, 1977). With this in mind, the between lat. 36°18' and 36°30'N in lations. Growth estimates have already effect of fishing on production of larvae 1976 but not in 1977 even though nine been presented. No estimates of mortal­ by a population of shortbelly rockfish bottom trawl hauls were made in the ity rates were found in the literature. was estimated. Fish were assumed to area in 1977. Most large midwater Often the rate of natural mortality (M) spawn once at the beginning of the catches were taken by trawling close to is approximately equal to k (Beverton year, the maturity schedule and the bottom. The midwater trawl catches and Holt, 1959). Thus a first approxi­ fecundity-age relationship described in averaged higher than the bottom trawl mation of M is 0.275. Of 1,081 the Biology section were used, and catches, 3,728 and 1,952 kg, respec­ shortbelly rockfish aged from rockfish fishing rates were assumed to be equal tively, probably because bottom trawls survey catches the oldest were 12 years for males and females. The results (Fig. were set at preselected stations, while old, which is older than the lO-year 9b) indicated that fishing would have a maximum age reported by Phillips considerable effect on relative fecun­ (1964). It is likely that, if M is sig­ dity (production of larvae of fished nificantly lower than 0.275, older fish stock/production of larvae of unfished would occur in the samples. Indeed, a stocks), and that relative fecundity is higher value ofM would be reasonable. very sensitive to age at recruitment at Table 1.-Catches of shortbelly rockfish. Sebastes jor- dani. that exceeded 450 kg in onl>-half hour bottom and Assuming that natural mortality is higher levels of fishing mortality, midwater trawls during 1977 rockfish survey and 1976 constant and that fishing mortality is pilot survey. Review of Rockfish Survey constant beyond age at recruitment, I Position at begin- Depth (m) Results With Regard To Fishing ning of tow used the Ricker (1958) yield equation to Bot- Catch Dale La! (N) Long. (W) Gear tom (kg) estimate yield per recruit at three ages N umbers of catches of shortbelly Bot/om trawls of recruitment: 2, 3, and 4 years. Re­ rockfish exceeding 450 kg (1,000 8-15-76 36'42' 121'58' 101 101 459 8-19-76 36'20' 122'3' 212 212 627 sults of the calculations indicate that pounds) were made by O. 5-hour bottom 8-19·76 36'30' 122'0' 177 177 4,120 yield per recruit is not sensitive to age and midwater trawls during the rockfish 7-18·77 35'33' 121'12' 132 132 519 7-27-77 36'59' 122'22' 124 124 4.722 of recruitment at F (fishing mortality) survey and a pilot survey (Gunderson 7-27-77 37"10' 122'43' 176 176 881 3 values less than 0.25 (Fig. 9a). When F and Nelson ) in the Monterey area dur- 7-30-77 37'19' 122'50' 144 144 2,790 7-30-77 37'18' 122'53' 240 240 2,499 is greater than 0,25, yield per recruit for 8-4·77 38'21 ' 123'25' 144 144 954 3Gunderson, D., and M. Nelson. 1977. Prelimi­ recruitment at ages 3 or 4 is greater than Midwater trawls nary report on an experimental rockfish survey when age at recruitment is 2 years. 8-12-76 36"56' 122'20' 154 229 3.314 conducted off Monterey, California. and in 8-13-76 37'11' 123'48' 302 302 3,156 There is little difference in yield per Queen Charlotte Sound, Blitish Columbia, dur­ 8-13-76 37'12' 122'50' 282 285 1,415 recruit when age at recruitment is 3 or4 ing August-September 1976. Unpubl manuscr, 8-19-76 36'18' 122'3' 161 165 3,313 82 p. Northwest and Alaska Fisheries Center. 8-20-76 36'21' 122'0' 274 274 7.264 for the values of F between 0,05 and NMFS, NOAA, 2725 Montlake BI vd. E., Seat­ 7·27- 77 37'13' 122'48' 245 247 4,055 0.4. tle, WA 98112. 7·27-77 37'21' 122'52' 188 192 3,578

38 Marine Fisheries Review midwater trawling was directed at con­ catches were composed of target used. Kato has tentatively estimated centrations detected through echo species: Chilipepper; bocaccio; that the price to fishermen would be sounding. darkblotched rockfish, S. crameri, about $100 to $200 per ton. Actual Aimed midwater trawling could Dover sole, Microstomus pacificus; rex prices, of course, will depend on a prove to be an efficient method of har­ sole, Glyptocephalus zachirus; and number of economic factors that can vesting shortbelly rockfish which form jack mackerel. only be evaluated by fishermen and large, off-bottom schools which are The by-catch in a shortbelly rockfish processors, and negotiations between readily detected by echo sounding. The fishery evidently can be kept at low the two parties. survey work indicated that with rela­ levels by using only midwater trawls, High catch rates are necessary to tively little experience fishermen could but it would also be desirable to control support a fishery for a species that has a learn to distinguish shortbelly rockfish age at recruitment. If mesh size restric­ price range between $100 and $200 per from other abundant school ing species tions prove impractical in accomplish­ ton. It would probably be necessary for such as Pacific whiting which is the ing this, the relationships between size a vessel to capture 10 to 20 tons per day species most likely to contribute to un­ and age composition with depth and to exceed operating costs. In addition to wanted by-catches. area of bottom trawl hauls indicated operating costs, capital outlays would Because of the small size of that fishermen may be able to minimize be necessary to equip bottom trawlers shortbelly rockfish, trawls would have catches of relatively small or young for midwater trawling. to be constructed of mesh size smaller shortbelly rockfish by choice of depth While the potential market, large than allowed for bottom trawls by and area fished (Fig. 3,4). Similar rela­ biomass, and large catches shown in California regulations, 4.5 inches tionships are apparent between depth of Table I indicated that there is consider­ (11.43 cm). Cod ends used in the haul and length compositions of large able potential for development of a rockfish survey were constructed of catches of shortbelly rockfish made by fishery for shortbelly rockfish, assis­ 1.25-inch (3.18 cm) webbing. Mesh midwater trawls. Five out of nine large tance by government agencies may be size experiments are required to deter­ catches were made at depths exceeding necessary for fullfillment of the poten­ mine optimum size for shortbelly 182 m (99.5 fathoms), and fish smaller tial. Kato has begun the development rockfish. than 200 mm fork length were not process by locating potential markets, The present California regulations caught in significant numbers at these purchasing appropriate fishing gear, are designed to prevent capture of depths. Thus it appears that, at least and working with fishermen and pro­ flatfish and other rockfish that are during summer, fishermen may be able cessors in initiating a test fishery. smaller than desired. Thus by-catches to minimize catches of small shortbelly Management Options For of other fish should be considered. In rockfish through choice ofdepth fished. Fishery Development the belief that fishermen targeting on If mesh size restrictions prove practi­ shortbelly rockfish would limit their ef­ cal, it appears that catches would be Management (State of California, fort to areas producing large catches of maximized by fishing at relatively deep Pacific Fishery Management Council, shortbelly rockfish, catch compositions depths. and U.S. Department of Commerce) of hauls that produced more than 450 kg has the option of either allowing or not Potential for Development of shortbelly rockfish were compiled allowing a fishery for shortbelly of the Fishery for bottom and midwater trawls made rockfish to develop. An argument during the rockfish and pilot surveys. S. Kato, a fishery biologist specializ­ against development of a fishery is that The catch by weight of species other ing in fisheries development at the shortbelly rockfish have been shown to than shortbelly rockfish was considera­ Tiburon Laboratory of the NMFS be prey items for important species bly higher for bottom trawling (23.67 Southwest Fisheries Center, has iden­ such as chinook salmon (Merkel, percent) than for midwater trawling tified several potential markets for 1957). On the other hand, Merkel's (3.04 percent). Most of the by-catch shortbelly rockfish. There may be a study showed that while shortbelly was Pacific whiting for midwater trawl­ small export market for good quality rockfish composed about 16 percent of ing, while the by-catch for bottom whole frozen fish. Another possible use the food of chinook salmon, 51 percent trawling was dominated by chilipepper; is canning for either pet or human con­ of the food was composed of northern bocaccio; Pacific whiting; jack macker­ sumption, and a small test pack found anchovy, Engraulis mordax, Pacific el, Trachurus symmetricus; and spiny the product acceptable as pet food. A herring, Clupea harengus pallasi, and dogfish, Squalus acanthias. Only 0.54 possibly very large market exists for squid (mostly Loligo opalescens). Sig­ percent of the midwater trawl catches use as a raw product for surimi. The nificant fisheries have existed on these were composed of target species of flesh appears to be of suitable quality species without any documented evi­ domestic fishermen: Chilipepper, for surimi, but their small size may dence of causing feeding problems for bocaccio, and sablefish. A relatively make shortbelly rockfish more expen­ chinook salmon. In addition Merkel es­ high 10.39 percent of the bottom trawl sive to process than species currently timated that euphausids composed 15

March-April 1980 39 percent of the food of chinook salmon. mates of stock size. Hydroacoustic Dewees, C. M. 1970. Population dynamics and Since shortbelly rockfish mainly feed midwater trawl surveys probably could fishing success ofan artificial reef in Humboldt Bay, California. M.S. Thesis, Humboldt State on euphausids (Phillips, 1964), they be designed to produce estimates of Univ., Arcata, Calif., 77 p. may compete with chinook salmon. stock size in areas of high densities of Follet, W I., and D. G. Ainley. 1976. Fishes collected by pigeon guiliemOls, Cephus col­ Management also has the option of the species at relatively low cost. If the umba (Pallas), nesting on southeast Farallon placing restrictions on types of gear, above data indicate the possibility of Island, California. Calif. Fish Game62:28-31 seasons, and locations. The results of more than one important stock, appro­ Gunderson, D. R. 1972. Evidence that Pacific ocean perch (Sebasres alurus) in Queen Char­ this study suggest that it may be advis­ priate studies should be carried out to lotte Sound form aggregations that have differ· able to allow the use of midwater trawls determine the stock structure. Finally, ent biological characteristics. J. Fish. Res. additional work, such as predator-prey Board Can. 29: 1061 -1070. but not bottom trawls because of rela­ Gunderson, DR., and T. M. Sample. 1980. tively large by-catches of species other studies, on the position of shortbelly Distribution and abundance of rockfish off than shortbelly rockfish when bottom rockfish in the community is desirable. Washington, Oregon, and California during 1977. Mar. Fish. Rev. 42(3-4):2-16. trawls are used. While yield per recruit Ideally, management should take into Hallacher, L. E. 1977. Patterns ofspace and food and population fecundity analyses indi­ account the effect of fishing on use by inshore rockfishes (Scorpaenidae: cated that age at recruitment should shortbelly rockfish on both its predators Sebasres) of Carmel Bay, California. Ph.D. Thesis, Univ. Calif., Berkeley, 115 p. probably be 3 or 4 years if a significant and competitors. However, as is the Hobson, E. S., and J R. Chess. 1978. Trophic fishery develops, information is not case for other marine fisheries, little is relationships among fishes and plankton in the known on the interactions of shortbelly lagoon at Enewetak Atoll, Marshall Islands. available to make specific recommen­ Fish. Bull., U. S. 76: 133-153. dations on obtaining that age at re­ rockfish with other species. Hubbs, C. L., A. L. Kelly, and C. Limbaugh. cruitment. The data (available only for 1970. Diversity in feeding by Brandt's cor­ morant near San Diego. Calif. Fish Game summer months) indicated that fisher­ Acknowledgments 56: I56- I65. men may be able to avoid capture of Larson, R. J. 1977. Habitat selection and territo­ small fish by choice of fishing depths Much of the data used for this report rial competition as the caw,es of bathymetric segregation of sibling rockfishes (Sebasres). and locations. No data are available on was collected by the 1977 rockfish sur­ Ph.D. Thesis, Univ. Calif.. Santa Barbara, the practicality of using mesh size re­ vey and the 1976 pilot survey. The ef­ 170 p. Merkel, T. J 1957. Food habits of the king salm­ strictions as a means to obtain a desired forts of the skippers, crews, and scien­ on Onchorhynchus rshawylscha (Walbaum), size at recruitment. Mesh size experi­ tific parties of the vessels John N. in the vicinity of San Francisco, California. ments and test fishing are required to Cobb, Commando, Miller Freeman, Calif. Fish Game 43:249-270. Miller, D. 1., and 1. 1. Geibel. 1973. Summaryof determine the correct policy for obtain­ David Starr Jordan, Pal San Marie, blue rockfish and lingcod life histories: a reef ing a specific size at recruitment. and Pacific Raider are appreciated. ecology study; and giant kelp, Macrocysris Estimates of a large biomass of Special thanks are due to D. R. Gun­ pyrifera, experiments in Monterey Bay, California. Calif. Dep. Fish Game, Fish Bull. shortbelly rockfish (295,000 t in a small derson and M. O. Nelson of the NMFS 158,137 p. portion of its range) indicated that the Northwest and Alaska Fisheries Center _____, and R. N. Lea. 1972. Guide to the coaslalmarine fishesofCalifomia. Calif. Dep. population could support a large and H. G. Moser and S. Kato of the Fish Game, Fish Bull. 157, 235 p. fishery. However, the relatively low NMFS Southwest Fisheries Center for Moser, H. G., E. H. Ahlstrom, and E. M. fecundity of the species suggests that freely supplying unpublished informa­ Sandknop. 1977. Guide to the identification of scorpionfish larvae (family Scorpaenidae) in caution in developing the fishery would tion and reviewing this paper. the eastern Pacific with comparative notes on be prudent. A relatively small fishery, species ofSebasles and Helicolenus from other e.g., 5,000-10,000 t of fish, may be oceans. U. S. Dep. Commer., NOAA Tech. Literature Cited Rep. NMFS Circ. 402, 7 I p. desirable until more is known about the Murphy, G. I. 1977. Clupeoids. In J. A. Gulland species. A small test fishery would Abramson, N. J. 197 I Computer programs for (editor), Fish population dynamics, p. 283­ allow development of procedures to ob­ fish stock assessment. FAO Fish. Tech. Pap. 308. John Wiley & Sons, N.Y. 101, var. pag. Phi lIips, J. B. 1957. A review of the rockfishes of tain desired size at recruitment through Beverton, R. 1. H., and S. J Holt. 1959. A California (family Scorpaenidae). Calif. Dep. mesh size experiments and monitoring review of the life spans and mortality rates of Fish Game, Fish Bull. 104, 158 p. fish in nature, and their relation to growth and 1964. Life history studies on ten ofsize and age composition of the catch other physiological characteristics. In G E. species of rockfish, (genus Sebastodes). Calif. with respect to depth and area of catch. W. Wolstenholme and M. O. Conner (editors), Dep. Fish Game, Fish Bull. 126,70 p. Location and extent of areas containing Ciba Foundation colloquia on ageing, Vol. 5. Ricker, W. E. 1958. Handbook of computations The lifespan of animals, p 142-177. Little, for biological statistics of fish populations. high densities of fish would provide Brown, Boston. Fish. Res. Board Can., Bull 119,300 p. more information on size of the Carlson, H. R., and R. E. Haight. 1972. Evi­ Sorokin, V P. 1961. The redfish; gametogenesis dence for a home site and homing of adult and migrations of the Sebasles marinus (L.) stock(s). Further analyses of larval sur­ yellowtail rockfish, Sebasresfiavidus J Fish. and Sebasles menrella Travin. Rapp. P.- V. vey data may provide additional esti- Res. Board Can. 29:1011-1014. Reun. Cons. Int. Explor Mer 150:245-250.

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