Preface.Acknowledgements.Introduction.Form and Function.Origin and Evolution.Nautilus: The Survivor.Biodiversity and Zoogeography.Life Cycle.Growth.Physiological Ecology.Reproductive.From Egg to Recruitment.Coastal and Shelf Species.Oceanic and Deep-Sea Species.Cephalopods as Predators.Cephalopods as Prey.Fishing Methods and Scientific Sampling.Fishery Resources.Fisheries Oceanography.Assessment and Management.Conclusions.Appendix A: Classification of Living Cephalopod Families.Appendix B: Synopsis of Living Cephalopod Families.References.Index.

Cephalopods: Ecology and Fisheries

Cephalopod reproductive strategies are reviewed in order to clarify their current, confusing status. Based on the type of ovulation, spawning pattern and growth between egg batches or spawning periods, five comprehensive and flexible cephalopod reproductive strategies are defined. Accordingly, with these three factors the following classification is proposed. (a) Spawning once (formerly semelparity) consisting of simultaneous terminal spawning, with synchronous ovulation, monocyclic spawning and absence of growth between egg batches. (b) Spawning more than once (formerly iteroparity) including: (i) polycyclic spawning with egg-laying occurring in separate batches during the spawning season and growth occurring between production of egg batches and spawning seasons; (ii) multiple spawning, with group-synchronous ovulation, monocyclic spawning and growth between egg batches; (iii) intermittent terminal spawning, with group-synchronous ovulation, monocyclic spawning and no growth between egg batches; (iv) continuous spawning, with asynchronous ovulation, monocyclic spawning and growth between egg batches. Examples of species exhibiting each of these reproductive strategies are given. The large amount of inter-species variation in several life-history traits related to reproductive events is discussed.

A review of reproductive strategies in cephalopods

The study of cephalopod populations currently lacks the means to define populations adequately and to resolve basic systematic confusions Quantitative data are usually only available from indirect sources such as commercial fisheries and from estimates of consumption by higher predators Despite these methodological difficulties it is clear that cephalopods comprise a major component of biomass globally, throughout all fully marine habitats Life-cycle characteristics common to the coleoids - early and/or semelparous breeding, rapid growth, short lifespan, little overlap of generations, vulnerability to predation and environmental variables - result in wide inter-annual fluctuations in abundance Most of the pelagic forms also undertake large- or meso-scale migrations which, coupled to shifting patterns of oceanographic variables, contribute to the unpredictability of distribution and density associated with many cephalopod species Temporal and spatial patterns of breeding, seasonality, growth, recruitment and mortality are clearly evident in most of the better-studied species But exceptions to pattern (eg variable growth rates, extended breeding, complex recruitment) also seem to be important intrinsic characteristics Levels of genetic variation in cephalopods are relatively low, and their population dynamics appear to be influenced principally by phenotypic plasticity in response to environmental variability In such universally short-lived species the maintenance of this diversity balances the risks of mortality factors combining at any one time to cause periodic local extinction The extent and scale of the interactions between cephalopod populations and other trophic levels suggests that major ecological perturbations such as environmental shifts, or imposed effects such as commercial fishing, whether directed at cephalopods or other species, are likely to have an impact on their populations As short-lived species with high turnover of generations, plastic growth and reproductive characteristics, high mobility and catholic predatory habits, they are always poised to respond to changed balances in their environment Studies on cephalopod populations have expanded considerably in numbers and scope in the last 25 years, driven by increased interest in and recognition of their roles in the marine ecology, as well as their increasing value as globally exploited resources Despite these recent advances, the information and concepts arising from their study is only slowly entering mainstream biological thought and becoming accommodated in broad-scale models of the marine ecosystem

Cephalopod populations: definition and dynamics

http://digital.csic.es/bitstream/10261/53738/3/Life_history_Loligo.pdf

The life history of Loligo vulgaris and Loligo forbesi (Cephalopoda: Loliginidae) in Galician waters (NW Spain)

Post-recruit Illex argentinus were collected from the fishery on the Patagonian Shelf between 1986 and 1988. Age was determined by analysis of daily growth increments in ground sections of the statolith, female fecundity was determined, specimens were dissected, weighed and assigned a maturity stage. The relation between mantle length and age is best approximated by a linear model. Both sexes live approximately one year. Females grow faster and attain a larger size than males, but males mature younger. Hatching occurs during the austral winter, peaking in June-July. There is a consistent trend of increasing growth rate with later date of hatching. Statolith growth is negatively allometric with body growth and there is greater divergence between statolith and body growth in females. In post-recruit Illex growth in mass of somatic tissues, apart from the digestive gland, approximates isometry with growth of the whole body. Growth of the digestive gland and the reproductive organs is positively allometric with growth in whole body mass. There is poor correlation between the female reproductive organs and whole body mass, which is due to differences in size at maturity. Mating rarely occurs on the feeding grounds. Fecundity of fully mature females in the sample falls in the range 113835-246098 eggs per individual. This possibly underestimates average fecundity because mature squid on the feeding grounds may be precocious and smaller than average at full maturity. A model combining absolute and relative growth, predicts average male and female growth and growth of the major somatic and reproductive organs. This poorly predicts average female maturity indices with age because of variability in mass of the female reproductive organs. A model that treats maturity stages separately gives close agreement with measured mass of the reproductive organs and maturity indices of a mature female at age one year. Females invest approximately 20% of total body mass in gonad and accessory reproductive organs at full maturity.

https://www.jstor.org/stable/pdfplus/76882.pdf

Dynamics of Growth and Maturation in the Cephalopod Illex argentinus de Castellanos, 1960 (Teuthoidea: Ommastrephidae)

Indirect evidence suggests that Stenoteuthis oualaniensis is a multiple spawner, a reproductive strategy not reported previously for squid. After spawning once, S. oualaniensis apparently continues to feed, grow, and mature additional oocytes before spawning again. Squid were caught by jigging at night in waters around the main Hawaiian Islands during four cruises from 1981 to 1987. All females from 200 mm mantle length (ML) to at least 318 mm ML were sexually mature, indicating that considerable growth takes place after reaching sexual maturity. Size-frequency analyses of ovarian oocytes revealed continuous egg production throughout adult life. Mature ova are stored in the oviducts, but oviduct fullness is unrelated to body size, indicating repeat spawning.

Evidence for multiple spawning in the tropical oceanic squid Stenoteuthis oualaniensis (Teuthoidea: Ommastrephidae)

Indirect evidence suggests that Stenoteuthis oualaniensis is a multiple spawner, a reproductive strategy not reported previously
for squid. After spawning once, S. oualaniensis apparently continues to feed, grow, and mature additional oocytes before spawning again. Squid were caught by jigging
at night in waters around the main Hawaiian Islands during four cruises from 1981 to 1987. All females from 200 mm mantle length (ML) to at least 318 mm ML were sexually mature, indicating that considerable growth takes place after reaching sexual maturity. Size-frequency analyses of ovarian oocytes revealed continuous egg production throughout
adult life. Mature ova are stored in the oviducts, but oviduct fullness is unrelated to body size, indicating repeat spawning.

Evidence for multiple spawning in the tropical oceanic squid Sthenoteuthis oualaniensis (Teuthoidea: Ommastrephidae)

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

T. Suzuki

Author Tools

Chat about Author

Papers

Evidence for multiple spawning in the tropical oceanic squid Stenoteuthis oualaniensis (Teuthoidea: Ommastrephidae)

Evidence for multiple spawning in the tropical oceanic squid Sthenoteuthis oualaniensis (Teuthoidea: Ommastrephidae)