MARC Record from Oregon Libraries

LEADER: 03151cam a2200397Ia 45e0
001 17286739
003 OCoLC
005 20050221122820.0
008 871228s1962 oruab b s000 0 eng d
040 $aOEL$cOEL$dOCLCQ
043 $an-us-or
049 $aOREU
050 4 $aQL430.7.S6$bH57 1962
090 $aSH11$b.O74 no.27
090 $aSH11$b.O74 no.27
100 1 $aHirschhorn, George.
245 10 $aGrowth and mortality rates of the razor clam (Siliqua patula) on Clatsop Beaches, Oregon /$cGeorge Hirschhorn.
260 $aPortland, Or. :$bFish Commission of Oregon,$c1962.
300 $a55 p. :$bill., map ;$c25 cm.
490 1 $aContribution / Oregon Fish Commission,$x0097-3548 ;$vno. 27.
500 $a"June 1962."
504 $aIncludes bibliographical references (p. 54-55).
530 $aAlso issued online.
505 0 $aIntroduction -- Physical features of Clatsop beaches -- Methods and objectives of sampling -- Length-weight measurements -- Age determination -- Variations in linear growth -- Relative width -- Age-length and age-weight -- Mortaility rates -- Yield calculations -- Discussion -- Summary -- Acknowledgments -- Literature cited.
520 3 $aClatsop Beaches, characterized by flat beach-face slope (1:70) and small sandsize (0.2 mm.), have supported commercial and recreational fisheries for the razor clam (Siliqua patula) for many years. Tracing the linear growth of two year classes through more than one year following set led to a validation of the ring method of age determination in the population studied. Annual ring lengths based on the means of samples from all subareas were fitted by von Bertalanffy equations. Increases in total length, wet weight, and relative width showed patterns of seasonal variation. Death rates of the Seaside Beach population were estimated from recoveries of 3,379 serially marked razor clams. Mortality coefficients obtained were: 2.52 for total mortality, based on the difference between estimated population sizes in 1952 and 1953 of year classes fully recruited at the beginning of the census; 1.78 for the estimated removals by actual harvesting; and 0.74 for other losses to which fishery-connected wastage was believed to have contributed, in addition to true natural mortality. The weight yield per 1,000 recruits, as function of age at first capture, was examined at three hypothetical levels of wastage indicating that potential increases in yield at each level could be realized by deferring the exploitation of a year class until its second year of age, regardless of whether the fisheries are continuous or seasonal.
650 0 $aRazor clams$zOregon$zClatsop County$xGrowth.
650 0 $aRazor clams$xMortality$zOregon$zClatsop County.
710 1 $aOregon.$bFish Commission.
830 0 $aContribution (Oregon. Fish Commission) ;$vno. 27.
856 41 $uhttp://hdl.handle.net/1957/3017$zConnect to this title online
907 $a.b23669524$bmulti$c-
902 $a070309
998 $b1$c050221$dm$ea$f-$g0
945 $lvcp $aSH11$b.O74$d120011447261$e1$uno.18-29
945 $lhgeg $aSH11$b.O74$d120007567395$e2$uno.21-29
945 $lngen $e1