Simple Size-Structured Models of Recruitment and Harvest in Pacific Salmon (Oncorhynchus spp.)

1994 ◽  
Vol 51 (3) ◽  
pp. 603-616 ◽  
Author(s):  
L. Scott Forbes ◽  
Randall M. Peterman
Keyword(s):  
Reproductive Success ◽  
Pacific Salmon ◽  
Reproductive Potential ◽  
Size Composition ◽  
The Body ◽  
Optimal Size ◽  
Small Fish ◽  
Total Biomass ◽  
Large Fish ◽  
Fish Harvest

Growing evidence suggests that in Pacific salmon (Oncorhynchus spp.), components of reproductive success besides fecundity are size dependent. However, managers setting escapement goals usually estimate reproductive potential of a stock in terms of total number of spawners, number of female spawners, or potential egg deposition given a mean size of spawners. Interannual variation in size composition of spawners may thus result in errors in assessing reproductive potential. Here, we develop models of recruitment and harvest and determine optimal size-selective harvesting strategies. These optimal strategies range from the current large-fish harvests (larger-than-average fish are caught, leaving smaller fish to spawn) to small-fish harvests, where the reverse is true. If the body mass (M) of individual spawners increases more rapidly than reproductive success (RS) with respect to increasing length of adult females (e.g., if number of eggs alone best measures RS), then sustainable biomass yield is maximized by the current large-fish harvest. However, if RS/M increases with increasing length of females (e.g., if total biomass of eggs best measures RS), then small-fish harvest maximizes sustainable yield. Evidence suggests that some salmon populations show this latter pattern; thus, large-fish harvests may generate suboptimal yields.

Pectoral fin locomotion in the striped surfperch. I. Kinematic effects of swimming speed and body size

1996 ◽  
Vol 199 (10) ◽  
pp. 2235-2242 ◽  
Author(s):  
E Drucker ◽  
J Jensen
Keyword(s):  
Body Size ◽  
Swimming Speed ◽  
Beat Frequency ◽  
Limited Range ◽  
The Body ◽  
Small Fish ◽  
Large Fish ◽  
Pectoral Fin ◽  
Transition Speed ◽  
Speed Up

Swimming trials at increasing velocity were used to determine the effects of steady swimming speed on pectoral fin kinematics for an ontogenetic series of striped surfperch Embiotoca lateralis, ranging from 6 to 23 cm in standard length (SL). The fin stroke cycle consisted of a propulsive period, the duration of fin abduction and adduction, and a 'refractory' period, during which the fin remained adducted against the body. Pectoral fin-beat frequency (fp) measured as the inverse of the entire stride period, as in past studies, increased curvilinearly with speed. Frequency, calculated as the reciprocal of the propulsive period alone, increased linearly with speed, as shown previously for tail-beat frequency of fishes employing axial undulation. Fin-beat amplitude, measured as the vertical excursion of the pectoral fin tip during abduction, increased over a limited range of low speeds before reaching a plateau at 0.35­0.40 SL. Pectoral fin locomotion was supplemented by intermittent caudal fin undulation as swimming speed increased. At the pectoral­caudal gait transition speed (Up-c), frequency and amplitude attained maxima, suggesting that the fin musculature reached a physiological limit. The effects of body size on swimming kinematics differed according to the method used for expressing speed. At a given absolute speed, small fish used higher stride frequencies and increased frequency at a faster rate than large fish. In contrast, the relationship between fp and length-specific speed (SL s-1) had a greater slope for large fish and crossed that for small fish at high speeds. We recommend that comparisons across size be made using speeds expressed as a percentage of Up-c, at which kinematic variables influencing thrust are size-independent.

scholarly journals The relation between concentrations of ovarian trace elements and the body size of Atlantic cod Gadus morhua

2008 ◽  
Vol 65 (7) ◽  
pp. 1191-1197 ◽  
Author(s):  
A. Bang ◽  
P. Grønkjær ◽  
B. Lorenzen
Keyword(s):  
Trace Elements ◽  
Body Size ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
The Body ◽  
Small Fish ◽  
Female Size ◽  
Large Fish ◽  
Size Category ◽  
Linear Discriminant

Abstract Bang, A., Grønkjær, P., and Lorenzen, B. 2008. The relation between concentrations of ovarian trace elements and the body size of Atlantic cod Gadus morhua. – ICES Journal of Marine Science, 65: 1191–1197. Trace metals in the ovaries of fish are transferred from the female via the yolk to the offspring, which makes the early life stages susceptible to deleterious effects of potentially toxic elements contained in the ovaries. Here, the concentrations of 13 elements from the ovaries of 133 ripe female North Sea cod Gadus morhua weighing 0.2–18 kg were correlated with female size, accounting for differences in maturity and condition. Most elements were negatively correlated with the size variables weight, length and, especially, ovarian dry weight. Further, they were negatively correlated with maturity and condition. Many of the trace elements showed true size-dependence, but the correlations were generally weak. A linear discriminant analysis separated “small” and “large” fish at a length of 85 cm based on concentrations of Co, Mn, Se, and Zn, and correctly assigned 78 of 102 small fish and 23 of 31 large fish to their respective size category. This corresponds to an overall classification success of 75.9%. The results suggest that embryos and early larvae from small females are exposed to higher levels of potentially harmful metals. If the differences in trace element concentration influence survival success, this will add to the negative effects of size distribution truncation and declines in size-at-maturity experienced by many populations of cod.

Consequences of microhabitat selection for reproductive success in the parasitic copepod Neobrachiella spinicephala (Lernaeopodidae)

Parasitology ◽  
2010 ◽  
Vol 137 (11) ◽  
pp. 1687-1694 ◽  
Author(s):  
J. T. TIMI ◽  
A. L. LANFRANCHI ◽  
R. POULIN
Keyword(s):  
Reproductive Success ◽  
Body Mass ◽  
Sampling Site ◽  
Attachment Site ◽  
Parasitic Copepod ◽  
The Body ◽  
Small Fish ◽  
Microhabitat Selection ◽  
Fitness Effects ◽  
Attachment Sites

SUMMARYNarrow site specificity in parasites is assumed to be associated with fitness benefits, such as higher reproductive success, although this is never quantified. We linked the body mass and combined mass of egg sacs of female copepods, Neobrachiella spinicephala, parasitic on the sandperch, Pinguipes brasilianus, to attachment sites on the host. Adult females attach permanently either on the lips, the margins of the operculum, or the base of pectoral or pelvic fins. In addition to influences of sampling site, season and host body length, our analyses revealed important fitness effects. First, attachment site significantly influenced copepod body mass; independent of other factors, copepods at the base of fins were 32% larger than those on the lips or operculum. Second, the mass of egg sacs was almost always greater if the copepod was attached at the base of fins rather than to the lip or operculum. Thus, a female weighing 6 mg would, on average, produce 40% larger egg sacs if attached to the base of fins. However, copepods were much more likely to attach at the base of fins on small fish, and on either the lip or the operculum on large fish. We propose that constraints varying with fish size account for the shift from optimal to suboptimal attachment sites as a function of increasing host size. By measuring differences in fitness components between attachment sites, our approach allows hypothesis testing regarding microhabitat selection.

scholarly journals I.—Preliminary Note on a New Specimen of Squatina from the Lithographic Stone of Nusplingen, Würtemberg

1898 ◽  
Vol 5 (7) ◽  
pp. 289-291 ◽  
Author(s):  
Arthur Smith Woodward
Keyword(s):  
The Body ◽  
The Other ◽  
Small Fish ◽  
Large Fish ◽  
Lateral Aspect ◽  
Anterior Border ◽  
Preliminary Note ◽  
The One ◽  
Similar Development ◽  
Lower Kimmeridgian

Several specimens of extinct species of the angel-fish or monk-fish (Squatina) are already known from the Lithographic Stone (Lower Kimmeridgian) of Bavaria, Würtemberg, and France; and some of these are in an admirable state of preservation. Two forms are clearly distinguishable—the one a small fish not more than 0·15 m.inlength, with a dense armour of rounded dermal tubercles on the anterior border of the head and each of the paired fins, and upon the lateral aspect of the tail; the other a comparatively large fish, attaining a length of at least a metre, without any similar development of the dermal tubercles, either in the regions mentioned or on any other part of the body.

Perception of the risk of contamination through feeding in pregnant and breastfeeding women

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
M Company-Morales ◽  
A Fontalba-Navas ◽  
M F Rubio-Jimenez ◽  
V Gil-Aguilar ◽  
J P Arrebola
Keyword(s):  
Fruits And Vegetables ◽  
Cumulative Effect ◽  
The Body ◽  
Primary Data ◽  
Toxic Substances ◽  
Large Fish ◽  
Structured Interviews ◽  
Chemical Substances ◽  
Synthetic Chemicals ◽  
Harmful Effects

Abstract Introduction Persistent Toxic Substances (PTS) are substances that are characterized by the cumulative effect at low doses inside the body. Exposure to PTS in pregnant and breastfeeding women, through food consumption, shows various harmful effects on the health of the mother, the fetus and the baby. The objective of this article is to analyze how pregnant and breastfeeding women perceive the presence of chemical substances in food and reflect on the accumulation, transmission and elimination of these substances. Methodology Descriptive and interpretive study under the qualitative research paradigm following a phenomenological and ethnographic perspective. As instruments to obtain the primary data we rely on 111 semi-structured interviews with pregnant and breastfeeding women, 4 focused ethnographies, 8 focus groups (63 women), 71 feeding diaries, 71 free listings. To encode the content of the speeches of pregnant and nursing women we rely on the N-Vivo 12 software. Results Pregnant and breastfeeding women are concerned about food quality controls. Women trust on local and seasonal foods such as fresh fruits and vegetables from non-extensive crops and close to their home. Foods that produce distrust in women are processed, packaged foods, red meat and large fish. The latter foods promote in women a perception of risk of contamination by chemical substances, manifesting a defenseless situation to maintain a diet without contaminants. Conclusions Pregnant and breastfeeding women in Spain have no information on the risk and danger of synthetic chemicals or PTS, with the exception of certain toxic substances such as mercury present in large fish. Women maintain a duality in their own care and that of the fetus or child. This circumstance implies that the women interviewed believe that PTS and synthetic chemicals may have different harmful effects on the mother and the degree of growth of the fetus and, subsequently, of the baby. Key messages Future mothers are worried about the type of product they eat, knowing that food influences healthy growth and development of the fetus. Pregnant and breastfeeding women often distrust “processed” or “industrial” foods, which they tend to associate with low quality and large amounts of additives and chemical substances.

scholarly journals Relation of Automated Body Condition Scoring System and Inline Biomarkers (Milk Yield, β-Hydroxybutyrate, Lactate Dehydrogenase and Progesterone in Milk) with Cow’s Pregnancy Success

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1414
Author(s):  
Ramūnas Antanaitis ◽  
Vida Juozaitienė ◽  
Dovilė Malašauskienė ◽  
Mindaugas Televičius ◽  
Mingaudas Urbutis ◽  
...  
Keyword(s):  
Lactate Dehydrogenase ◽  
Reproductive Success ◽  
Milk Yield ◽  
Body Condition ◽  
Body Condition Score ◽  
The Body ◽  
Time Analyzer ◽  
Condition Score ◽  
Pregnancy Status ◽  
Body Condition Scoring

The aim of the current study was to evaluate the relation of automatically determined body condition score (BCS) and inline biomarkers such as β-hydroxybutyrate (BHB), milk yield (MY), lactate dehydrogenase (LDH), and progesterone (mP4) with the pregnancy success of cows. The cows (n = 281) had 2.1 ± 0.1. lactations on average, were 151.6 ± 0.06 days postpartum, and were once tested with “Easy scan” ultrasound (IMV imaging, Scotland) at 30–35 d post-insemination. According to their reproductive status, cows were grouped into two groups: non-pregnant (n = 194 or 69.0% of cows) and pregnant (n = 87 or 31.0% of cows). Data concerning their BCS, mP4, MY, BHB, and LDH were collected each day from the day of insemination for 7 days. The BCS was collected with body condition score camera (DeLaval Inc., Tumba, Sweden); mP4, MY, BHB, and LDH were collected with the fully automated real-time analyzer Herd Navigator™ (Lattec I/S, Hillerød, Denmark) in combination with a DeLaval milking robot (DeLaval Inc., Tumba, Sweden). Of all the biomarkers, three differences between groups were significant. The body condition score (BCS) of the pregnant cows was higher (+0.49 score), the milk yield (MY) was lower (−4.36 kg), and milk progesterone in pregnant cows was (+6.11 ng/mL) higher compared to the group of non-pregnant cows (p < 0.001). The pregnancy status of the cows was associated with their BCS assessment (p < 0.001). We estimated that cows with BCS > 3.2 were 22 times more likely to have reproductive success than cows with BCS ≤ 3.2.

Size Changes, Mortality, and Equilibrium Yields in an Exploited Stock of American Plaice (Hippoglossoides platessoides)

1969 ◽  
Vol 26 (5) ◽  
pp. 1205-1235 ◽  
Author(s):  
P. M. Powles
Keyword(s):  
Mesh Size ◽  
Food Competition ◽  
Mortality Factor ◽  
Otter Trawl ◽  
Small Fish ◽  
Large Fish ◽  
Age Composition ◽  
Instantaneous Rate ◽  
Factors Affecting ◽  
Ecological Dominance

Records from research surveys and commercial landings for American plaice from the Magdalen Shallows, or the southwestern Gulf of St. Lawrence, showed decreases in percentage of old, large fish and in catch per unit of effort from 1955 to 1962. The changes in age composition were clearly relatable to the fishery, which was mainly by otter trawl. Ricker models indicated that wastage of deck-exposed subcommercial plaice is currently a greater mortality factor than predation by cod. Increased landings in particular years were associated with successful year-classes. Other factors affecting landings were annual differences in fleet dispersal, which were related to movements of cod, a cohabiting species. No clear decrease or increase in absolute recruitment of plaice was demonstratable because quantitative comparisons of research surveys by different vessels using different gears and with different skippers, would be misleading.Mortality estimates of adult plaice by three methods showed agreement, indicating that instantaneous rate of natural mortality was between 0.09 and 0.13. The instantaneous rate of fishing for 1957–62 was 0.46. Increasing mesh-size would reduce cod catches and have little effect in conserving plaice, but marketing small fish would increase plaice landings. Voluntary release of small plaice promptly on capture would help maintain the stock, as would reduction in numbers of large cod, the main predator of small plaice. Increased numbers of small cod since 1959, as reported by other workers, could result in greater food competition with small plaice, effectively reinforcing the ecological dominance of cod over plaice.

scholarly journals Fishery-induced changes in Norwegian red king crab (Paralithodes camtschaticus) reproductive potential

2013 ◽  
Vol 71 (2) ◽  
pp. 365-373 ◽  
Author(s):  
Ann Merete Hjelset
Keyword(s):  
Egg Production ◽  
Barents Sea ◽  
Reproductive Potential ◽  
Size Composition ◽  
Red King Crab ◽  
Paralithodes Camtschaticus ◽  
King Crab ◽  
Males And Females ◽  
Induced Changes ◽  
Individual Fecundity

Abstract Hjelset, A. M. 2014. Fishery-induced changes in Norwegian red king crab (Paralithodes camtschaticus) reproductive potential. – ICES Journal of Marine Science, 71: 365–373. The introduced red king crab (Paralithodes camtschaticus) in the Barents Sea supports a valuable fishery in northern Norway. In this paper, I examine the effect of the increased harvest rate and the recently added female quota on the potential egg production of the stock. The size ranges of males and females in the period 1995–2011 were recorded, and estimated stock abundance of ovigerous females and established individual fecundity parameters from 2000–2007 were used to assess the reproductive potential of the stock from 1995–2011. The upper size ranges of males and females decreased throughout the period studied, presumably mainly due to fishing. The change in size composition among ovigerous females and functional mature males, and the reduced mean individual fecundity in the stock seem to have had a negative effect on the potential egg production of the stock.

Ntrauterine programming of women’s health as a determinant of the reproductive potential of a population

2017 ◽  
pp. 10-15
Author(s):  
L.G. Nazarenko ◽  
◽  
N.S. Nestertsova ◽  
Keyword(s):  
World Literature ◽  
System Development ◽  
Reproductive Potential ◽  
The Body ◽  
Large For Gestational Age ◽  
Relevant Research ◽  
Gynecological Diseases ◽  
The World ◽  
Oncological Diseases ◽  
The Relationship

The relationship between the body weight of women at birth and the development in the future of gynecological diseases or deviations in the development of the reproductive system, development of oncological diseases and the timing of menopause have been analyzed. The results of clinical studies conducted at different times in different countries of the world, which cover the topic of this article, are presented. An overview of the world literature presented in the article, substantiates the relevance of conducting relevant research in the Ukrainian population. Key words: low birth weight, large-for-gestational-age fetus, gynecology disease.

scholarly journals Lifetime reproductive success in a population of female red kangaroos Macropus rufus in the sheep rangelands of western New South Wales: Environmental effects and population dynamics

2004 ◽  
Vol 26 (1) ◽  
pp. 45 ◽  
Author(s):  
AD Bilton ◽  
DB Croft
Keyword(s):  
Population Dynamics ◽  
Reproductive Success ◽  
Environmental Conditions ◽  
New South ◽  
New South Wales ◽  
Reproductive Potential ◽  
Lifetime Reproductive Success ◽  
South Wales ◽  
Macropus Rufus ◽  
Initial Starting

Female reproductive success and the recruitment of offspring to the next generation are key components of animal population dynamics. With an annual commercial harvest of between 13 and 22% of the red kangaroo (Macropus rufus) population, it is increasingly important that these processes are understood. We used data on the reproductive success of 33 free-ranging female M. rufus on Fowlers Gap station in far western New South Wales to determine the expected lifetime reproductive success (LRS) of females within an unharvested population. We also designed a model to generate predictions about female LRS incorporating empirical relationships between a mother?s reproductive success and maternal age, environmental conditions and the sex and survivorship of a previous reproductive attempt. Results from observations on female LRS (calculated from annual weaning rates) and those generated by the model predict that female M. rufus on ?Fowlers Gap? wean, on average, 3.7 young in a lifetime (ranges 0 - 11 and 0 - 20, respectively); representing only 41% of their maximum reproductive potential. Manipulation of initial starting conditions allowed the effect of varying environmental conditions on female LRS to be explored. The condition of the environment when females commence breeding does not appear to significantly affect their overall lifetime reproductive output. However, the occurrence of drought does. Females experiencing two droughts in a lifetime did not live as long and weaned fewer offspring and grandoffspring (from their daughters) than those females experiencing only one drought in a lifetime. In addition to the adverse effect of drought on the reproductive success of female M. rufus in this study, we suggest that, given the relatively high and stable population densities of M. rufus on ?Fowlers Gap?, other mechanisms (acting primarily on juvenile survival) must exist which limit population growth.

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