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Overfishing Social Fish

January 2025
Fish and Fisheries 26(2):278-290

DOI:10.1111/faf.12880

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Authors:

James Wilson

University of Maine

Jarl Giske

University of Bergen

Culum Brown

Macquarie University

Social learning is common among vertebrates, including fish. Learning from others reduces the risk and costs of adaptation. In some longer‐lived species, social learning can lead to the formation of persistent groups that pass learned adaptations from one generation to the next (culture). Variations in learned adaptations are subject to natural selection, leading to a second, fast‐paced, fine‐scale evolutionary process that complements genetics and enables adaptation to the peculiarities of local areas. Socially learned knowledge is stored mainly in the minds of older fish and subsequently inherited (learned) by younger fish. Consequently, the persistence of locally adapted groups of long‐lived fish requires the inheritance of genetic and learned adaptations. Local populations of social learners are not often recognised nor conserved by fisheries managers. Fishing usually reduces the relative abundance of older fish far more than younger. We hypothesise that fishing may impair and eventually erase the learned local adaptations of long‐lived fish, leading to the loss of local stocks of these species and significant ecosystem‐wide changes. Fishing may shift abundance towards species not dependent on learned adaptations, i.e., invertebrates and short‐lived fish. The hypothesis leads directly to the idea that conserving populations of long‐lived social learners is likely best accomplished by protecting age and social structure or, more generally, the natural processes, such as social learning, that generate complexity in an adaptive ecosystem. Local area‐based management is aligned with the local processes of social learners and can capture and learn about the effect of human activity at that scale.

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Fish and Fisheries, 2025; 0:1–13

https://doi.org/10.1111/faf.12880

1 of 13

Fish and Fisheries

ORIGINAL ARTICLE OPEN ACCESS

Overfishing Social Fish

JamesA.Wilson1 | JarlGiske2 | CulumBrown3

1School of Marine Sciences, University of Maine, Orono, Maine, USA | 2Department of Biological Sciences, University of Bergen, Bergen, Norway | 3School

of Natural Sciences, Macquarie University, Sydney, Australia

Correspondence: Jarl Giske (jarl.giske@uib.no)

Received: 18 October 202 4 | Revised: 17 December 2024 | Accepted: 18 December 2024

Funding: The authors received no specific f unding for this work.

ABSTR ACT

Social learning is common among vertebrates, including fish. Learning from others reduces the risk and costs of adaptation.

In some longer- lived species, social learning can lead to the formation of persistent groups that pass learned adaptations from

one generation to the next (culture). Variations in learned adaptations are subject to natural selection, leading to a second,

fast- paced, fine- scale evolutionary process that complements genetics and enables adaptation to the peculiarities of local areas.

Socially learned knowledge is stored mainly in the minds of older fish and subsequently inherited (learned) by younger fish.

Consequently, the persistence of locally adapted groups of long- lived fish requires the inheritance of genetic and learned adapta-

tions. Local populations of social learners are not often recognised nor conserved by fisheries managers. Fishing usually reduces

the relative abundance of older fish far more than younger. We hypothesise that fishing may impair and eventually erase the

learned local adaptations of long- lived fish, leading to the loss of local stocks of these species and significant ecosystem- wide

changes. Fishing may shift abundance towards species not dependent on learned adaptations, i.e., invertebrates and short- lived

fish. The hypothesis leads directly to the idea that conserving populations of long- lived social learners is likely best accomplished

by protecting age and social structure or, more generally, the natural processes, such as social learning, that generate complexity

in an adaptive ecosystem. Local area- based management is aligned with the local processes of social learners and can capture

and learn about the effect of human activity at that scale.

1 | Introduction

In the four or five decades since the creation of exclusive

economic zones, global marine fish landings have stabilised

(FAO 2022) but with ‘a gradual transition from long- lived,

high trophic level, piscivorous bottom fish toward short-

lived, low trophic level invertebrates and planktivorous pe-

lagic fish’ (Pauly et al. 1998). As Pauly and others (Frank

et al. 2005; Howarth et al. 2013; Myers and Worm 2005;

Steneck et al. 2011; Jackson et al. 2001; Worm et al. 2006;

Shears and Babcock2002; Synnes etal.2023; Eriksson etal.

2024) point out, these patterns are symptomatic of a simpli-

fied and possibly unstable ecological structure. We also point

out that these patterns suggest the recovery of long- lived, high

trophic- level fish appears much slower than of other system

components. Hauser and Carvalho(2008) present interesting

and complementary evidence derived from molecular genet-

ics suggesting that among fish, there is ‘extensive differenti-

ation and biocomplexity’ with ‘effective population sizes 2–6

orders of magnitude smaller than census sizes’. Using otolith

chemistry, Kerr etal.(2024) come to similar conclusions, i.e.,

finer- scale population structures. Together, these studies sug-

gest that the usually assumed structure and dynamics of fish

populations and the outcomes of fishing differ significantly

from conventional perceptions.

Like many of our colleagues, we have sifted through the evi-

dence and the various theories about how fish and humans

This is a n open access ar ticle under the terms of t he Creative Commons Attr ibution License, which p ermits use, dis tribution and repro duction in any medium, p rovided the orig inal work is

properly cited.

2 of 13 Fish and Fisheries, 2025

interact, hoping to find insight into these and other puzzling

observations. A long list of candidates is reviewed by Howarth

et al. (2013), Worm, Hilborn, and Baum (2009), Jackson

etal.(2001) and others. Social learning among fish is an over-

looked possibility that we believe should be on the shortlist. In

extensive summaries, Whiten(2021) and Brakes et al. (2019)

note that social learning, when one animal learns from another,

is a second system of adaptation that complements genetics, en-

abling adaptation at a fine spatial and at a faster temporal scale.

Social learning affects the diverse local niches fish develop, the

size of self- reproducing populations and, generally, the diver-

sity and complexity of the natural system. Older age and social

learning are closely related. In a recent survey, Kopf etal.(2024)

reviewed how older members benefit a population. The attribu-

tion of sentience among fish is not common in fisheries science,

maybe because it is not thought to have a pervasive effect on

the structure and dynamics of fish populations. In contrast, our

interest here is in how consideration of social learning among

longer- lived, typically higher trophic- level fish affects our un-

derstanding of the demographics and dynamics of these species

and, consequently, our understanding of the impacts of fishing

on individual populations and the rest of the ecosystem.

Social groups among animals, especially vertebrates, are com-

mon and well- known—a pack of wolves, a flock of birds, a pod

of whales, a school of fish, etc. There is strong evidence that fish

can be socia l learners and that the behaviours ind icative of social

learning appear common among fish (Brown and Laland2003;

Brown and Webster 2024). We find this significant because, as

we explain below, the effects of fishing on populations of social

learners appear to lead to outcomes broadly consistent with the

worldwide shift towards invertebrates and short- lived fish iden-

tified by Pauly etal.(1998) and the finer- scale population struc-

ture that is apparent when using refined methods to identify

effective populations as argued by Hauser and Carvalho(2008),

Kerr et al. (2024) and others. Consequently, we conclude that

understanding the demographic and behavioural effects of so-

cial learning among fish is essential to understanding the prob-

lem of overfishing.

For fish that learn, the peculiar variations in any local1 area's

physical and biological environment are the fodder for new,

specific learned behaviours (Wilson and Giske2023). Variations

in topography, sediment types, macroalgae, water currents,

prey, predators, competitors and other relevant aspects of a fish's

local environment can lead to learned adaptations that benefit

the individuals directly involved (Ginsburg and Jablonka2019)

and, insituations where social learning occurs, the other mem-

bers of the group (Brown and Laland2011) and, in some circum-

stances, subsequent generations (Laland and Evans 2017). The

local scale and rapid pace of these peculiarities do not usually

lead to genetic specialisation. However, social learning does

allow for rapid and continuous adaptation to local variations

and, as a result, gives rise to time and place behaviours unique

to the different places the species inhabits.

Consideration of social learning suggests that the sustainabil-

ity of local populations of social learners and local ecosystems

depends on the inheritance of two bodies of adaptive knowl-

edge—genetic and socially learned (Wilson and Giske 2023;

Budaev etal.2019). The inheritance of socially learned knowl-

edge, i.e., culture (Boyd and Richerson 1985; Laland and

Hoppit t 2013), tends to be significant to longer- lived species

that can take advantage of longer- term regularities in a local

area. Loss or impairment of this socially learned, locally ap-

propriate adaptive knowledge is likely to affect the local stock

directly. If this local outcome is repeated in many places, it

may lead to substantial impacts elsewhere in the ecosystem.

These likely effects of social learning and its possible loss lead

us to an alternative interpretation of the mechanisms and out-

comes of fishing. These ideas can be stated as a hypothesis

(Figure1):

Long- lived social fish rely on social learning to

adapt to the peculiarities of local areas, forming

local sub- populations, or stocks, in the process.

Socially learned knowledge important to local

adaptation is stored mainly in the minds of

older fish and subsequently inherited (learned)

by younger fish. Fishing tends to preferentially

remove older fish, impairing or erasing the learned

adaptations of local populations of long- lived, social

FIGUR E  | Our social learning hypothesis. Local adaptation of long- lived fish requires genetic (black arrow) and learned (grey arrow) inter-

generational knowledge. Fishing tends to remove older fish, the source of learned long- term adaptive knowledge. Extirpation is the eventual result.

Artwork by Iylarose Willis.

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3 of 13

species and inducing substantial disruptions in the

adaptations of the local population's prey, predators,

and competitors.

Social learning suggests significant non- genetic adaptation and

leads naturally to a view of system organisation and dynam-

ics that emphasises the role of ‘information and adaptation’

(Krakauer2024). From this perspective, our hypothesis argues

that the information, i.e., the knowledge, long- lived fish require

for successful adaptation is genetic and socially learned; fishing

impairs or removes the socially learned knowledge essential to

that adaptation.

The sections of the paper that follow flesh out the reason-

ing that leads to our hypothesis. We begin (section2) by ex-

plaining social learning among fish, emphasising the role of

information and adaptation. We pay particular attention to

the organisational and demographic consequences and the

requirements for reproducing socially learned adaptations.

We then (section 3) use the same social learning perspective

to introduce the idea that the commercial fishing industry

is an invasive population of very smart social learners. The

interaction of fish and fishers—both social learners—gen-

erates distinct patterns of exploitation that appear to con-

form with the observations of Pauly etal.(1998), Hauser and

Carvalho(2008) and others cited above. In the final sections

of the paper, we briefly consider the out- of- the- ordinary sci-

entific questions and the fisheries management implications

raised by the consideration of social learning.

2 | Social Learning, Culture and Population

Structure Among Long- Lived Fish

Not so long ago, fishes were often viewed as mindless autom-

atons, pre- programmed to respond to environmental cues in

predictable ways, as if their behaviour was ruled only and en-

tirely by their genes. However, as more is learned about animal

behaviour, that view is quickly fading. During the Cambrian

explosion, early vertebrates emerged with the cognitive ca-

pacity for subjective experience (Feinberg and Mallatt 2013;

Ginsburg and Jablonka2010, 2019; Godfrey- Smith2017) and

episodic- like memor y (Schultz 2024; Zacks, Ginsburg, and

Jablonka2022) that have enabled learning, planning and co-

operation (Busia and Grigg io2020; Croft etal.2006; Heathcot e

et al. 2017). Over the last several decades, research has re-

vealed that fishes' cognitive capacity and behavioural flexi-

bility are not overly different from most vertebrates (Brown,

Laland, and Krause 2011; Bshary and Brown 2014; Budaev

etal.2024; Giske etal.2025; Salena etal.2021). Import antly,

it has become apparent that while fish behaviour has essential

genetic components, it is also quickly adaptable due to the ca-

pacity for learning. Learning allows animals to fine- tune their

behaviour to adapt to changing local environments (Ginsburg

and Jablonka2019; Budaev etal.2019).

Fishes can learn about their environment through individual ex-

periences and interactions with others (Brown and Laland2011;

Brown2023). Rather than wasting time and energy and incur-

ring the ri sk of exploring its env ironment and a range of potential

behavioural responses, a social learner can adopt the behaviour

of others. The mechanisms by which this occurs are many and

varied. They may be as simple as a conspecific drawing atten-

tion to a particular object or location (stimulus or local enhance-

ment). They may also be complex, such as active teaching or goal

emulation (Heyes 1994). This flexibility means social learning

can inform behaviour in various contexts, including what to eat,

where and when food can be found, how to recognise predators,

who to mate with and which migratory pathways to use (Brown

and Laland2003).

Genetics gives individuals a hard- wired, persistent ‘memory’ of

tested adaptations that worked in the past over broad spatial and

temporal scales. In contrast, the memory of successful socially

learned adaptations resides in the ephemeral minds and bodies

of individuals. Learned memory content may vary considerably

among ind ividuals be cause indiv iduals' memories a re most likely

derived from recent local experiences (including learning from

others) and are likely to reflect their different experiences in a

complex environment. As a consequence, for the group, the adap-

tive value of individuals' memories may only be realised through

social cohesion that facilitates continuing local communication

(Weinrich, Hoppitt, and Rendell2013; Webster etal.2013) and a

collective decision process that resolves or minimises different

experiences (Bottinelli etal.2013). Consequently, natural selec-

tion also operates on the learned adaptive behaviours resulting

from a group decision process. It refines that collective decision

process, improving the adaptation of the cultural equivalent of

the group's gene pool, thus benefitting its individual members.

The very different mechanism of heritability of socially learned

adaptive knowledge means fishing is likely to affect the pro-

cesses essential for learned adaptation in ways that differ signifi-

cantly from its effect on genetic adaptation.

From a demographic perspective, social cohesion means per-

sistent associations emerge as local organisations or structures

important to broader population structure. The groups that form

this way can exploit niches and places that would otherwise be

too costly for an individual to adopt. For social learners, the col-

lective effect of the memories that arise with learning means

that the reasonably regular seasonal or longer- term events

that occur in a complex system and that an autonomous indi-

vidual would find very costly to learn are effectively acquired

at a low cost by large numbers of fish in a social setting (Clark

and Mangel1986). For example, herring appear to use the same

spawning sites each year. It is difficult to imagine millions of

autonomous individual fish independently learning those sites.

Many niche and spatial opportunities that would not otherwise

be possible are enabled. The once enormous biomass of large-

bodied, long- lived predators suggests their refined niches were

highly successful before fishing and that their loss due to fish-

ing has substantially affected the rest of the system (Myers and

Worm 2005; Jackson etal.2001; Pauly etal.1998; Hauser and

Carvalho2008).

2.1 | The Communication of Learned Adaptive

Knowledge

It is helpful to distinguish two ways learned information is

communicated because the organisational consequences are

significant. Sharing information about highly particular,

4 of 13 Fish and Fisheries, 2025

ephemeral local events can result in novel and short- lived

collective behaviour. For example, a group of fish may make

a beneficial discovery, e.g., a deadfall whale; when the bene-

fits of such an event dissipate, the individual and collective

memory of the dead whale has little value. Similarly, an indi-

vidual benefits substantially when its predators are detected

by other fish in its group. The particular knowledge of a prey

attack at that time and place likely has little value afterwards.

However, the benefits of the collective activity that generates

these kinds of f leeting benefits create strong incentives to as-

sociate with others of the same species. Those same associa-

tions can quickly spread information that reflects knowledge

of longer- term regularities. Usually, the intra- generational

communication of valuable socially learned ephemeral knowl-

edge is labelled horizontal transmission and may be common

among invertebrates and vertebrates.

The transfer of socially learned knowledge from one to subse-

quent generations is termed vertical transmission (Laland and

Hoppitt2013). The vertical transmission of adaptive knowledge

is most likely limited to longer- lived fish that might have the

capacity to benefit from knowledge of longer- term events, such

as appropriate spawning sites or complicated migration routes.

Notably, the variations in adaptive experience among individ-

uals (as noted above) and the transmission of this knowledge

across generations enable the natural selection and evolution of

learned adaptive behaviours and population organisation that

are appropriate to longer- term, regular local phenomena (Aplin

etal.2015; Brakes etal.2019; Boyd and Richerson1985; Keith

and Bull2017; Whiten2017, 2021).

Among long- lived fish, the intergenerational transfer of so-

cially learned knowledge, i.e., culture, differs from the trans-

fer of genetic information in two important ways. First, genetic

information is passed from parents to offspring once in a life-

time; in contrast, the transfer of socially learned knowledge

occurs continuously throughout an animal's life and can re-

sult from interactions with many unrelated individuals. It is

entirely possible that younger fish may pass their experience

to older fish. Consequently, social learning can spread well-

adapted behaviours quickly over periods significantly shorter

than a lifespan (Brown 2023). Second, it is usually assumed

that larval drift and adult fish movement act to distribute ge-

netic information over a potentially broad area. Consequently,

if genetics is considered the only heritable body of knowledge,

effective population size is defined accordingly. However,

this common fisheries management view is challenged by

the small- scale population structures identified by Hauser

and Carvalho (2008) using molecular genetics and by Kerr

etal.(2024) using otolith analysis.

In contrast with the standard view of large- scale populations,

the inheritance of socially learned knowledge is limited by the

restricted range of communication networks among fish. This

restriction leads to persistent local associations among indi-

viduals and finer- scale population structure. Consequently,

for longer- lived fish, the inheritance of genetic and socially

learned adaptive behaviours via persistent social groups is,

along with the inheritance of the adaptive knowledge in genes,

essential for individual growth, adaptation, survival and pop-

ulation sustainability. Further, the scale of self- reproducing

populations, i.e., those that pass on both genetic and learned

adaptations, corresponds with the limited range of fish com-

munications. Brakes et al.(2019) call these local population

units cultural variants.

2.2 | Myopia and Complexity

Understanding the agent- level mechanisms that lead to the

emergence of cultural variants and other aspects of natural

system dynamics is essential for understanding the human

impacts on the system. In a complex system, each agent—fish

or human—holds only a small part of the knowledge contrib-

uting to an orderly system (where we use the term ‘orderly sys-

tem’ to mean a system with enough predictability to manifest

the myopic expectations built into well- adapted behaviour).

Every individual has a subset of the experiences of past gener-

ations incorporated in its genes. When learning occurs, an in-

dividual can draw on its experience (Budaev etal.2024), and

if the individual is a member of a species of social learners, it

can also draw on the accumulated multi- generational expe-

rience of its social group. Thus, an individual's personal and

socially acquired experience and the experience of its social

group localise the individual's learned adaptive knowledge.

This knowledge is myopic because the learned experience

it draws upon is restricted to those evolved behaviours most

likely to benefit its local survival and reproduction. We don't

use the term myopic to mean very fine scale and restricted

to a particular place. Instead, the term refers to a focus on

only a small part of an extensive system, even if the focus has

multiple scales, e.g., the geographic knowledge that might

encompass seasonal migrations. We assume that when the

individual's current circumstances align with its experience

or knowledge, it will likely choose reasonably successful be-

haviour (Budaev et al.2019; Giske etal.2025). When its cir-

cumstances lie outside the realm of its acquired experience,

as might happen in a disturbed environment or with fishing,

we assume the likelihood of maladaptive behaviour increases

(Giske etal.2025).

Thus, adaptation, whether learned or genetic, generates cur-

rent behaviours that reflect successful past behaviours and,

for that reason, gives rise to a roughly predictable regularity

in the timing, circumstances, and location of events in the

system. This myopic knowledge governs the organisation and

behaviour of individuals and, consequently, group and inter-

group interactions. It is the basis for the complexity of the liv-

ing portion of the natural system. From the perspective of our

hypothesis, the conservation of the processes that generate

this information is essential to the complexity of the natural

system and critical to the sustainability of the system's evolved

organisation.

Social learning suggests that non- linear population dynamics

may be another source of complexity, at least for some exploited

populations in some circumstances. Like many information

phenomena, the growth and loss of culture among long- lived

fish are likely to be non- linear (Holland2012). Information

sharing across generations is most valuable when it extends

behaviours appropriate to longer- term regularities, such as

when and where to migrate and spawn (Huse, Railsback, and

5 of 13

Fernö 2002; Rose1993). If there were a uniform, clockwork-

like environment, natural selection would likely lead to uni-

form behaviour and a genetically built- in consensus (Baldwin

1896; Morgan 1896; Osborn 1897). In the absence of physical

change, the system would duplicate itself. In a variable en-

vironment, the behaviour of survivors is likely to be equally

variable, reflecting their sur vival in different environmental

circumstances. As a result, natural selection of well- adapted

behaviours will require a longer history, i.e., more older fish,

to sort out longer- term regularities. In a variable environment,

if collective decisions involve any kind of consensus, the self-

organisation of local culture will likely be a non- linear pro-

cess (Holland2012) that accelerates rapidly once a consensus

develops around well- adapted behaviours—more individuals

using the behaviours, leading to still more adopters, etc. The

disassembly of culture due to fishing may work the same way

but in reverse—less consensus, less individual benefit from

group experience, and fewer individuals to pass on adaptive

behaviours. Given the relatively fast pace of social learning,

these non- linearities may produce surprisingly quick changes

in population organisation. The few survivors of the local pop-

ulation that may be left after heavy fishing may not be able

to muster the knowledge required to maintain the inherited

local adaptation. Extirpation is the result. Genetic knowledge,

in contrast, is entirely contained in each fish's DNA and may

be recreated by only a few local survivors.

2.3 | The Fishing Relevant Demographic Effects

of Social Learning

In long- lived fish, the population dynamics that emerge from

social learning may differ significantly from those usually con-

ceived in fisheries theory and practical management. These dif-

ferences are significant because they change our understanding

of how fishing affects the natural system.

We focus on four significant differences.

• First, the reproduction of genetic and learned knowledge

is very different. A newly mature fish can pass its genes to

the next generation, whereas all the events over its life can

affect what is passed on to other individuals by social learn-

ing. Early in life, through numerous learning interactions,

a socially learning individual acquires the experience of

older fish as well as its own experiences. Later in life, it may

contribute these experiences to younger fish. This lifelong

process implies the need for a continuously cohesive local

social unit whose senior members are the principal reposi-

tory of the unique but continually changing body of knowl-

edge required for local adaptation (Whiten 2021; Brakes

etal.2019).

• Second, when local population renewal requires the inher-

itance of genetic and socially learned adaptive knowledge,

the scale of the communications that maintain coherent

local social groups sets the scale of their renewal, not the

broad scale usually assumed by managers who are gener-

ally thinking of broad- scaled genetic inheritance only.

• Third, each species will likely differ in its dependence

on social learning and the adaptive memories held by

older fish. Short- lived fish, such as anchoveta, living in

a pelagic environment with behaviours closely aligned

with physical processes, may benefit significantly from

the horizontal transmission of learned information such

as might occur when other fish signal that a predator is

near. However, their knowledge of appropriate responses

to changes in the physical environment is most likely in-

corporated in their genes, and their population range is

appropriately large, i.e., the range over which the infor-

mation in the genes is communicated. In contrast, the

adaptations of long- lived predators, living and migrating

between bio- diverse and highly variable environments,

e.g., cod and other large- bodied piscivores, may depend

significantly on the intergenerational transfer of inher-

ited, socially learned information pertinent to finer- scale

population structure and local adaptation.

• Fourth, among culture- dependent, long- lived social

learners, the non- linearities of cultural disassembly and

assembly (Holland2012) may be responsible for a surpris-

ingly sudden loss of local adaptive knowledge followed

by extended periods without recovery (Hutchings and

Myers1994), during which the collective knowledge gov-

erning local adaptation is rebuilt. For example, in Eastern

Maine the groundfishery collapsed in the early 1990s. An

on- going hook sur vey of the area begun in 2010 and con-

ducted by the Maine Center for Coastal Fisheries regu-

larly catches juvenile cod and other demersals, but until

this year, about 35 years since the collapse, the survey

has not caught any adults. This year (2024), it caught one

(Chen etal.2013; E. Ames, pers. com).

In the next section of the paper, we extend the ideas of social

learning to the commercial fishing industry, treating it as an

invasive, highly adaptive population in a complex adaptive

system.

3 | Commercial Fishing Considered as an Invasive

Population of Social Learners

Consideration of social learning among fish leads naturally to

the idea that commercial fishers might be conceived as a pop-

ulation of diverse, highly adaptive and fast- to- learn top preda-

tors. When thought of this way, the same information- centric

analytical framework described above for social learning in

fish, when applied to fishers, suggests a significantly differ-

ent interpretation of the causes, patterns and consequences of

overfishing.

Social learning among humans is much more consequential

than among fish. Language, writing, communications and de-

liberate institutions for accumulating and spreading knowledge

all contribute to social memory and its distribution (Arrow1962;

Ostrom 1990; Arthur1992). Fishing benefits greatly from this

broad social capacity. However, the complexity of the natural en-

vironment and the difficulty of observation means that the very

fine- grained temporal and spatial knowledge fishers require to

‘make a good set’ at any moment is largely outside any body of

collective knowledge. Small boat fishers working in complex en-

vironments are particularly versed in the knowledge of places

6 of 13 Fish and Fisheries, 2025

whose scale is appropriate to the scale of their gear, e.g., the res-

olution of hook fishers' knowledge of particular places is often

at a scale of a hundred metres or less. Their need to minimise

the costs of acquiring this information leads to particular spatial

and temporal patterns that are the basis for a different under-

standing of the patterns of fishing.

Fishing is all about search, i.e., acquiring and using environ-

mental knowledge at multiple scales (Wilson1990). Like fish,

fishers cope with the complexity of a vast system by focusing

on the regularities that occur in only a small part of the system.

The breadth of fishers' confident knowledge is limited mainly to

the restricted part of the system—the places, times, gear, other

fishers and species—that they find familiar. Their knowledge is

gained through direct experience, observing and talking with

other fishers, self- testing hypotheses about the time and place

fish might be caught and endless, but somewhat guarded, dis-

cussions about fishing and the market.

Significantly, fishers form groups that closely resemble the

information- sharing groups formed by social learning fish.

Williamson (1985) refers to these kinds of economic arrange-

ments as ‘clubs’; Acheson (1988), an anthropologist, prefers

‘gangs’. Among smaller- scale independent fishers, these groups

are informal, somewhat flexible associations of a small num-

ber of near equals (Acheson 1988; Wilson et al. 2013). Within

a group, fishers acquire their knowledge of fish through their

own experience and ‘horizontal’ communications with other

group members. Transfers of knowledge about longer- term reg-

ularities in the local fishery, i.e., ‘vertical’ transmissions, occur

through extended hands- on apprenticeships and extensive dis-

cussions within families and the community.

Unlike fish (perhaps), information sharing among humans is

subject to equity considerations. Among fishers and almost all

informal groups exploiting a common resource (Ostrom1990),

unwritten rules tend to exclude individuals who do not contrib-

ute proportionate valuable knowledge or other services to the

group (Acheson1988; Ostrom1990). Formal organisations, such

as industrial fishing operations, require written contractual ar-

rangements that replace the informality of small- boat fishing.

However, the fundamental need to share equitably, or at least

with reasonable certainty about the expected outcome, among

human social groups is present regardless of scale. These infor-

mation equity concerns reinforce the continuity of relationships

and organisation.

The knowledge fishers acquire from and share with others about

the location of fish tends to be about coarse- grained time and

place patterns. For example, ‘in the early spring, the fish tend

to move up off the soft bottom into the gullies along the edge

of the shelf’. Individual fishers remember particular places and

times, of course. Nevertheless, when they leave port, they aim

for the general areas where history and their most current in-

formation tell them fish might be. They don't attempt to predict

the specific location of fish. In any but the most uniform envi-

ronments, finding the exact location of fish at any moment is

the result of a very local search. That search is heavily depen-

dent on skill and experience, but even then, it is economical only

due to the focus provided by broader- scale collective knowledge.

In other words, fishers combine their essential myopia with a

typical hierarchical search (Holland2012). They begin by rely-

ing on broader scale, longer- term, slower- moving, collectively

held and generally cheaper information. They conclude with

the individual acquisition of faster- paced, much less predictable,

finer- grained and more costly information. Fishers' attempts to

minimise search costs appear to significantly influence the spa-

tial and species patterns of exploitation in the system (Wilson

etal.2013, 2000).

The informal organisations of fishers and long- lived, predatory

social fish share some interesting similarities. Both require

shared information, both form persistent groups for this pur-

pose, and both focus on a relatively restricted part of the system.

In other words, acquiring adaptive knowledge is costly (Wilson

et al. 2013) for fish and fishers, and the evolved solutions are

similar. Both also face what is sometimes called ‘the commons

problem’.

Neither fish nor fishers are likely to be aware of broader- scale

changes in the system brought about by their own and others'

myopia until those changes work their way through the system

and directly affect their current adaptation. Presumably, the

persistence of relatively stable systems is due to evolved external

restraints, not to self- restraint (Wilson and Wilson2007). Thus,

a natural system with myopic fish can be relatively stable in the

sense that most species persist despite wide swings in abun-

dance. Myopic fishers have the same capacity for unrestrained

self- destruction, except their exceptional flexibility may extend

their activity to many species and induce significant changes in

the ecosystem. In the next to the last section of the paper, we

comment on the kinds of external restraint that fishing in a com-

plex system might require.

4 | Simplifying the Complexity of the System

Understanding a complex system requires some form of simpli-

fication, i.e., a strategy that allows one to conceive of the sys-

tem without having to acquire the information that defines its

‘infinite complexities’. Standard fisheries theory approaches

(or avoids) complexity by focusing on single- species dynamics,

ignoring the natural system's extensive interactions. We reach

for simplicity by focusing on two patterns of commercial fishing

(considering the industry as an invasive species) that remove es-

sential organising information from the natural system. These

patterns are relatively general and found in the interaction of

fishing with almost all exploited species.

• The first is commercial fishing's strong tendency to

truncate the age structure of local populations (Pauly

et al. 1998) and, consequently, to weaken or elimi-

nate those populations' socially learned adaptive local

knowledge.

• The second is the economic incentives and social learning

among fishers that spread the same loss of adaptive knowl-

edge to multiple species at multiple places.

Simplifying the system from this perspective is helpful because

it leads to a better understanding of the web of ecosystem effects

emanating from the invasive effects of fishing.

7 of 13

The effects of a truncated age structure: Fishing has a strong

tendency, with some exceptions,2 to truncate the age structure

of exploited populations. Bigger fish are often targeted because

they bring a better price in the market. Still, even without that

preference, the longer fish live, the more frequent their expo-

sure to fishing. As a result, their relative abundance is reduced

much more than that of younger fish or older fish in unfished

populations. It follows that the impact of fishing on long- lived,

culture- dependent populations is likely much more substantial

than among short- lived fish and invertebrates that are not de-

pendent on cultural adaptations.

In a culture- dependent population, as the proportion of older

fish declines, the vertical transmission of experience to younger

fish is diminished, social cohesion declines, and the adaptive ca-

pacity made possible by in formation sharing is weakened or lost.

Accordingly, the circumstances of indiv idual fish and groups are

more likely to lie outside the realm of their personal or learned

experience, and the likelihood of maladaptive actions increases.

Infrequent existential annual events like spawning locations

(Mason etal.2024; Warner1988) and migrations that are mainly

dependent on the memory of older fish are likely to be most af-

fected, e.g., herring (Huse, Railsback, and Fernö2002) and cod

(Rose1993). As a population's age structure is compressed, the

variability of its adaptive responses likely increases, and, even-

tually, with few or no older fish, a rapid, non- linear approach to

extirpation is the probable result. Extirpation means the experi-

ence that constitutes a local adaptation may be permanently lost

and irretrievable—the social learning equivalent of extinction.

When only one species in a local system is extirpated, it is rea-

sonable to expect that acquiring the beneficial experience that

constitutes a local adaptation may take time. If the extirpation in

the local ecosystem extends across multiple interacting species,

exponentially more time would seem likely. In contrast, fishing

down local aggregations of short- lived fish and invertebrates—

species that are not likely to depend on culture—is not likely

to threaten the loss of their more broadly applicable (genetics

only) adaptive knowledge. Thus, the pace of their renewal after

depletion is not likely constrained by the need to coevolve a new

adaptation with other species in the local area.

Spreading the effects of truncated age structure: As a local,

harvested population declines, economic incentives generate

a fundamental, profit- seeking dynamic that expands the im-

pact of truncated age structure to other economically valuable

local populations and different species in the system. To illus-

trate the dynamic, consider a broad area like the typical man-

agement zone; assume the area is a patchy conglomeration

that contains multiple populations of many species of inverte-

brates and fish, some of which are locally adapted, long- lived

social learners. Assume fishers share reasonably accurate but

coarse- grained information about the timing, likely location

and relative abundance of fishable aggregations. Also, assume

fishers face significant search costs, i.e., travel time, energy

and foregone local harvests. When fishing begins, fishers tar-

get valuable stocks and species close to home to reduce steam-

ing costs and because they are likely to be familiar with the

fine- scale behaviours of these stocks. As the abundance and

revenues of nearby opportunities decline, some fishers real-

ise the expected revenues from the greater abundance of more

distant opportunities or other species will compensate for the

greater risk, the costs of steaming and the costs of learning

about a new target. Other fishers notice and, along with the

initial explorer, shift their effort to different places and spe-

cies (Synnes et al. 2023 and citations therein, Ames 2004;

Sanchirico and Wilen1999). As this process continues, the re-

sult at any moment might be called a ‘bio- economic ideal free

distribution’ in which the relative profits (including discounts

for risk) of fishing at each location and species are moving in

the direction of equivalence. Despite individuals' attempts at

secrecy, information about new opportunities tends to spread

quickly. The resulting shift of effort to new stocks or species

is likely to be a quick, non- linear process. ‘All of a sudden,

everyone is fishing on the lower bank.’

There is no equilibrium. The process continually reallocates

fishing effort across fish stocks as the abundance of those

stocks varies in response to fishing and natural causes. In

general, costly search suggests that the effort assigned to each

local stock varies in a way that is inversely proportional to

risk, steaming and learning costs and directly proportional

to revenue. Consequently, the amount of fishing on the var-

ious exploited stocks will likely differ by species and place.

Because long- lived fish depend on culture, their response

to fishing will likely differ dramatically from non- culture-

dependent fish. The historical record tends to show the early

reduction and eventual extirpation of convenient, i.e., nearby

and inexpensive- to- fish, populations of long- lived social

species (Ames 1997). Only remote and costly- to- fish sub-

populations are likely to persist in the long run. Convenient

aggregations of invertebrates and short- lived social learners—

animals less dependent on culture—are likely to be affected

in ways consistent with standard, genetics only, theory. Still,

their abundance may deviate from what might be expected

due to significant changes in their biotic environment, such

as those that might occur with the removal of long- lived pred-

ators (Worm etal.2006; Steneck etal.2011). The populations

of remote and non- marketable species are likely to be less

disturbed, more abundant and contain a higher proportion of

older individuals.

5 | Summarising Our Hypothesis About Fishing

Social Fish in a Complex System

Social learning is a second method of adaptation that appears

common among fish. It operates at a faster pace and finer

scale than the broader scale genetics usually employed in fish-

eries management. Thus, social learning allows adaptation to

unique, longer- term local regularities that might not be possible

with genes alone. Among longer- lived fish, it may lead to the or-

ganisation of persistent, locally adapted stocks or cultural vari-

ants whose scale of renewal is finer than is usually assumed.

Consequently, the persistence of local stocks of social learners

requires the continuous inheritance of genetic and learned ad-

aptative knowledge.

Longer- lived species refine their local adaptations through so-

cial learning, but refinement increases their vulnerability to

fishing. Fishing disproportionately targets older, experienced

fish, impairing the collective memory of culturally dependent

8 of 13 Fish and Fisheries, 2025

species. As the group's collective experience declines, the com-

munication of adaptive experience to younger fish becomes

less regular and more haphazard. Socially learned knowledge

of infrequent but existential events such as seasonal shifts in

behaviour and annual migrations is the most likely to be lost

(Chambers2021; Huse, Railsback, and Fernö2002; Rose1993;

War ner 1988, 1990). As adaptive knowledge is lost, the be-

haviour of the local population becomes more variable and the

population less well- adapted and less abundant. Eventually,

local adaptation breaks down, with extirpation the likely

outcome.

Furthermore, fishers prefer to fish at times and places that

minimise the costs and maximise the revenues of harvesting.

As the abundance of economically convenient stocks declines,

typical economic incentives distribute fishing effort in a way

that tends to equalise longer- term profits across all fishable

areas and species. The process allocates disproportionately

more effort to convenient, well- known and cheaper- to- fish

stocks. Among long- lived social learners, this leads to a cas-

cade of extirpations (Baum and Worm 2009), starting with

the lowest- cost- to- fish local populations, generally coastal

and ending with costly- to- fish remote stocks. The loss of local

stocks of social learners is the equivalent of removing some of

the restraints that determine the impact of fishing on other

non- learning species, likely leading to significant indirect ef-

fects, such as those that might occur with the removal of pred-

ators, as noted by several authors (Worm etal.2006; Steneck

etal.2011; Howarth etal.2013; Jackson etal.2001). In short,

fishing tends to remove the adaptive knowledge essential to

the persistence of locally adapted populations of long- lived

social learners, leaving a species distribution that is consis-

tent with ‘a gradual transition from long- lived, high trophic

level, piscivorous bottom fish toward short- lived, low trophic

level invertebrates and planktivorous pelagic fish’ (Pauly

etal.1998).

Our hypothesis incorporates a perspective that departs from

the usual conception and practice of fisheries management in

three fundamental ways. The first concerns recruitment or the

requirements for the sustainability of populations of long- lived,

high trophic- level fish. Social learning among fish suggests

that the reproduction of culture, i.e., of local adaptations, is a

lifelong process dependent on a multi- age class social process

in which younger, less experienced fish learn from older, more

experienced individuals. The implication is that the sustain-

ability of local populations of social learners may require a co-

hesive, multi- age social unit for the successful inheritance of

learned adaptive knowledge (Wilson and Giske 2023; Budaev

etal.2019).

Second, when population renewal requires the socialisation

of young fish, the scale of renewal likely corresponds with the

range of social communications that support coherent social

groups. Fish communicate over relatively short distances.

Consequently, consideration of population renewal or sustain-

ability at a broad scale and only with respect to genetic recruit-

ment, as usually happens in standard fisheries management,

ignores the inheritance of learned local adaptive knowledge

and the fine- scale population structure relevant to the re-

newal of populations of long- lived social learners. If a local

population's social structure is strong enough to generate re-

productive isolation and is persistent, gene/culture interactions

(Boyd and Richerson1985) may explain the fine- scale popula-

tion structure revealed by the molecular genetic approach pre-

sented by Hauser and Car valho (2008), Kerr etal.(2024) and

others.

The third departure from the usual conception concerns social

learning among fishers (Wilson and Giske 2023). Fishers are

great learners, but the spatial and species patterns of exploita-

tion that result from their learning are rarely incorporated in

fisheries theory and management. Here, we treat the commer-

cial fishing industry as a population of highly adaptive, f lexible

and invasive social learners, effectively another component of a

complex adaptive system. Approaching the dynamics of the fish-

ing industry in this way suggests that the interactions between

humans and the natural system are likely to have causes and

patterns of overfishing and recovery that differ among social

learners and other species and that are significantly different

from those usually envisioned.

6 | Science Directions

We have hypothesised that sentience and learning among

fish and fishers might lead to significant demographic ef-

fects among fish and distinct patterns of human intervention

in the natural system. This perspective leads to questions

that are significantly different from those that usually ani-

mate fisheries science and suggests an alternative agenda for

fisheries. The list of questions below is motivated by a kind

of self- scepticism, that is, questions we'd like to ask to fill in

or test our knowledge of fisheries circumstances. We expect

tests along these lines to find the logical implications of social

learning consistent with real fisheries; however, we also know

that questions like these are just as likely to lead to the refine-

ment or (for some species) rejection of the ideas expressed in

the elaboration of our hypothesis. These bullets cover ques-

tions about the population structure and dynamics of long-

lived unfished social learners, questions about the response of

populations of social learners to fishing and questions about

the patterns of overfishing. While the questions are wide and

open, they are meant to stimulate consideration of the kinds

of scientific questions that arise when social learning is rec-

ognised. The bullets are not in any way meant to be a defini-

tive list of important questions.

• How do social behaviours and group dynamics influence

the population structure and dynamics of long- lived social

learners?

• At what point in life does the vertical, intergenerational

transmission of socially learned knowledge typically begin?

• Is social learning among short- lived fish and invertebrates

limited to horizontal transfer?

• What role do gene- culture interactions play in shaping the

fine- scale population structures of long- lived species?

• What are the consequences of truncating age structures and

disrupting social groups for the recruitment and persistence

of long- lived species?

9 of 13

• Do invertebrates and short- lived fish rebuild their popu-

lations faster than long- lived social learners in overfished

circumstances?

• Can broader- scale population collapses emerge from the

cumulative effects of local extirpations of long- lived fish?

In the early 1990s there was a widespread collapse of cod

stocks in the NW Atlantic? What was the cause of the near

simultaneity?

• How do the patterns of collapse differ between social learn-

ers and other overfished species like invertebrates or short-

lived fish?

• How do the behaviours and group dynamics of fishers in-

fluence fishing patterns, stock extirpations and the sustain-

ability of fish populations?

• What role does fishers' knowledge and the implementation

of area management play in promoting collective restraint

and sustainable fishing practices?

A final broad question concerns the ability to model these

kinds of questions. In most cases, questions like these will

not be amenable to deterministic models. However, it is possi-

ble to combine environmental heterogeneity, age- class struc-

ture, some genetics and both individual and social learning

with the use of individual- based modelling (Acerbi, Jacquet,

and Tennie2012; Acerbi and Tennie2016; Budaev etal.2024;

Grimm and Railsback 2005; Railsback and Grimm 2011;

Stillman etal.2015; van der Post and Hogeweg 2009; van der

Post, Ursem, and Hogeweg2009). Such model studies can guide

the empirical research that will also be needed.

7 | An Alternative Conservation Perspective

A social learning perspective emphasises the natural system's

spatial, organisational and temporal complexity. It also sug-

gests that quantitative manipulation of a complex system may

be significantly more complicated and prone to unintended

consequences than we imagine. The cornerstone of our hy-

pothesis is the idea that the adaptive knowledge of long- lived

fish is generated by both social learning and genetics. This

knowledge plays a vital role in the evolved complexity of the

system. Fishing tends to remove two critical components of

complexity—the learned adaptive knowledge held by older

fish and the continuing social structure necessary to retain

and modify the adaptation of long- lived social learners. For

these reasons, conservation efforts should aim to preserve the

processes that maintain the information that generates com-

plexity—socially learned knowledge and as usually assumed,

the adaptive knowledge in fish's genes.

Standard management policies assume a genetics- only repro-

duction dynamic. They ignore the critical role of learned ad-

aptations and have not conserved the diverse, patchy niches

generated by the experience of long- lived fish. As a result, the

restraints usually applied to fishing are designed to protect

only the genetic part of the renewability equation and may be

ineffective and often lead to perverse and unintended conse-

quences. For example, (1) rules concerning the minimum size

of capture are usually invoked to allow more newly mature

fish to spawn with the expectation that more eggs will make

adequate recruitment more likely. Unfortunately, when these

rules are implemented with larger mesh nets, as they usually

are, they make older fish more catchable and reinforce the

tendency to truncate age structure with all the adverse ef-

fects that follow. (2) Quotas are intended to ensure adequate

numbers of spawners. However, when a broad- scale quota is

applied to social learners, fishing on local populations is not

restrained in any meaningful way and, generally, leads to a

focus of fishing effort on particular, economically advanta-

geous stocks and a cascade of extirpations of local stocks. (3)

Broad- scale licensing for pursuing one or a few species is con-

sistent with the assumed scale and genetics- only recruitment

processes envisioned by single- species theory. However, when

applied to species of social learners or any species showing

local self- reproducing aggregations or patchiness, it does not

constrain and may accelerate the local- to- remote cascade of

extirpations. Furthermore, (4) with the possible exception of

closed areas, the current approach does not address ecosys-

tem effects. It provides no reason to expect the kinds of results

Pauly etal.(1998) and Hauser and Carvalho(2008) present.

Finally, and perhaps most troublesome, (5) broad- scale licens-

ing induces (almost requires) a mindset among fishers that is

principally concerned with where to fish next after local abun-

dance is reduced. In a management regime that allows fish-

ers to roam, those who do not roam are not survivors. Larger

mesh, quotas and roaming are a trifecta whose compounded

unintended effects are likely to hasten the simplification of

the complexity of the natural system.

The critical question is how to manage fisheries embedded in

a natural system with ‘infinite complexities’ (Darwin 1859).

Complex systems also exist outside the natural world, of

course. Most human societies are organised in ways compara-

ble with the complex hierarchical structure of natural systems

(Holland2012). Like natural systems, human systems are ca-

pable of infinite complexity. Over eons, humans have learned,

regardless of political mode, to govern their own complexity

through multilevel organisation. Responsibilities are divided

according to scale, minimising the information required for

governance at each level. Inter- scale problems are generally re-

solved through feedback and feedforward mechanisms focusing

on interscale problems only, minimising cross- scale informa-

tion costs. The reason for this close to universal organisation

appears to be the essential need to reduce the costs of the in-

formation required at each level of governance (Krakauer2024,

2011; Holland2012).

Our social learning hypothesis is fundamentally an argument

about how costly information affects the behaviour and the

organisation of the natural system at different scales. For ex-

ample, at a local scale, survival depends critically on the in-

dividual's ability to focus on a very restricted body of locally

relevant information. The required inheritance of learned

adaptive knowledge among long- lived social learners and

the restricted communication abilities of fish lead to the lo-

calisation of populations of social learners. In contrast, the

scale of populations of non- social learners corresponds with

the broad scale at which genetic information is transferred.

Thus, like other complex systems, the organisation of fisher-

ies systems tends to be multiscale and favours a hierarchical

10 of 13 Fish and Fisheries, 2025

organisation that minimises information costs (Ostrom 1990;

Krakauer2024; Holland2012).

In light of the above, we assume effective fisheries management

needs to be aimed at preserving the information processes that

create complexity in the natural system and organised to min-

imise the information cost of governance. Our social learning

hypothesis argues that the information problem in the natural

system arises from two mechanisms or tendencies of fishing:

first, the tendency to flatten the age structure of targeted pop-

ulations, leading to the loss of learned adaptive knowledge in

culture- dependent species. Second, there is a tendency for profit-

seeking fishers to spread the loss of adaptive knowledge to other

local stocks and species.

Addressing the truncated age structure problem is primarily a

problem of learning how to maintain older fish in local pop-

ulations of long- lived social learners. There has been a long

awareness of the important reproductive contributions of big,

old, fat, fecund, female fish—BOFFFFs (Hixon, Johnson, and

Sogard2014; Ahrens etal.2020). Here we add the idea that both

old females and old males contribute to the social reproduction

of local stocks (Warner1988, 1990). According to our hypothe-

sis, successful rules intended to keep older fish in a population

are likely to depend critically on the peculiarities of local condi-

tions. In many single species fisheries ‘slot rules’ (a minimum

and maximum size) are employed. The intended outcome of slot

policies is thoroughly consistent with the maintenance of social

learning processes. Nevertheless, we are sceptical about the

ability of any existing gear to make the necessary selections in a

fishery that catches multiple species, each of which would want

its own slot. It may be that local prohibitions on the times and

places of fishing may prove more selective and effective. Fish

may move in or out of particular places at different times; they

may segregate by age classes at some times and not others. They

may engage in various kinds and times of migration. There are

many possibilities, each one usually dependent on local circum-

stances. Understanding and adapting to these circumstances

depends critically on knowledge of the local system and a gov-

ernance system that can draw continuously on feedback about

the local system and the effect of fishing. Human learning has

to take place at the local scale. Local governance that aligns with

the organisation of a local system is critical to the interpretation

of feedback (Ostrom1990). The practical problem at each local-

ity will be understanding when and where to use different kinds

of gear or time and place prohibitions, i.e., selection restraints.

The development of a programme along these lines will have to

be based on a robust collaborative effort bringing together sci-

entists and fishers with locally relevant ecological knowledge.

It will also have to involve the development of new gear with

different selection properties. Furthermore, the required science

will need to lean towards the behavioural and ecological aspects

of the natural system rather than its large- scale population dy-

namics as described in the preceding section of the paper.

Preventing the spread of adverse local consequences most likely re-

quires area- based governance. In these circumstances, each area

is protected from intrusions of fishers from other areas, and, as a

result, each f isher in each area can expect t o share in the benefits of

local conservation, but only if the typical race to get the fish—the

commons dilemma—can be resolved. Local organisation means

there is a relatively small number of fishers; their knowledge of

each other and of the local system is likely to be similar, and the

interests of this smaller number are more likely to be relatively

homogeneous (Ostrom 1990; Wilson 2017). If higher- level man-

agement makes clear its intention to support local governance and

efforts to end ‘the race to fish’, a major stumbling block to collec-

tive action and mutual restraint is removed (Ostrom1990).

In these circumstances, before the commons dilemma has been

resolved but after spatial restrictions are in place, an essential

strategic question fishers ask themselves changes from ‘When

this place is fished out, where do I fish next?’ to ‘What might

happen in this place next year with mutual restraint this year?’

Fishers' self- interested economic incentives and the likely fea-

sibility of solving the commons dilemma at the local level may

incline fishers to collective action and leave them more likely to

engage actively with scientists (Wilson2006; Moller etal.2004;

Farr, Stoll, and Beitl2018).

Finally, it is crucial to recognise that localising the commons

does not isolate each local area. Fish move; various species

move at different times to different places and are likely to cross

any formal boundaries of local fish management. For example,

coastal stocks may retreat to deeper waters in the winter, where

they might mix with other local stocks. Many pelagic species

migrate seasonally in patterns that take them across any con-

ceivable set of local boundaries. Cross- boundary circumstances

like these create a situation in which one group of local fishers

may find it profitable to harvest fish another group has been try-

ing to conserve. Suppose a migration crosses several local area

boundaries. In that case, fishers at either end of the migration

and those along the migration route might be tempted to operate

an intercept fishery, but each one is also anxious that no other

area does the same. In other words, localisation of governance

can potentially convert a broad- scale, degenerate race for the fish

into circumstances in which fishers from the affected local areas

have strong incentives to engage in mutually beneficial restraint.

In short, our hypothesis argues that the conservation of a com-

plex, multiscale natural system requires the preservation of the

adaptive knowledge essential to system organisation. To under-

stand the natural system and to engage in effective mutual re-

straint, human organisation must be roughly aligned with the

multiscale organisation of the natural system.

Author Contributions

Conceptualisation: James A. Wilson, Jarl Giske and Culum Brown.

Writing – original draf t: James A. Wilson, Jarl Giske and Culum Brown.

Final text: James A. Wilson, Jarl Giske and Culum Brown.

Acknowledgements

We thank Geir Huse, Michael Fogarty, Ted Ames, Robin Alden, Robert

Steneck, Larry Mayer, Nancy K nowlton, Ed itor Gar y Carvalho, and t wo

anonymous reviewers for their thoughtful comments and perspectives,

and Iylarose Willis for the artwork in Figure1.

Data Availability Statement

The paper contains no data and builds on reading the literature we

have cited.

11 of 13

Endnotes

1 When we use the term ‘local stock or sub- population’, we refer to a

socially formed subset of a larger population; we do not think of ‘local’

as a particular place or as a set of geographical circumstances. Over

the course of a year, a socially cohesive local stock may be the exclusive

representative of its species to occupy a particular area. At other times

it may move to and share with other local populations different places

such as an overwintering refuge. If social processes lead to reproduc-

tive isolation, genetics may also take on a local manifestation.

2 An interesting counter example is the now defunct juvenile herring

fishery in Atlantic Canada and New England. Initially, in the late

1800s and for the next 100 plus years, the fishery deliberately avoided

the capture of older fish in order to focus on juveniles that could be

canned and marketed, misleadingly, as canned sardines. The avoid-

ance of adults was accomplished through time- and- place- based fish-

ing that used weirs and stop seines in the shallow coves and inlets

that juvenile herring, but not adults, retired to in the evening. Various

pieces of legislation reinforced a ban on the nearshore use of purse

seines that supplied adult and bait markets. The fishery for cannery

sized fi sh existed for over a centur y but was quickly exting uished when

with the appearance of new markets for adult fish in the 1970s and 80s

and the subsequent relaxation of regulations led to the use of purse

seines and mid- water trawls and the loss of older fish (Judd1988).

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Herring spawned poleward following fishery-induced collective memory loss

Article

Full-text available

May 2025
NATURE

Entrainment is a process in schooling migratory fish whereby routes to suitable habitats are transferred from repeat spawners to recruits over generations through social learning¹. Selective fisheries targeting older fish may therefore result in collective memory loss and disrupted migration culture². The world’s largest herring (Clupea harengus) population has traditionally migrated up to 1,300 km southward from wintering areas in northern Norwegian waters to spawn at the west coast. This conservative strategy is proposed to be a trade-off between high energetic swimming costs and enhanced larval survival under improved growth conditions³. Here an analysis of extensive data from fisheries, scientific surveys and tagging experiments demonstrates an abrupt approximately 800-km poleward shift in main spawning. The new migration was established by a large cohort recruiting when the abundance of older fish was critically low due to age-selective fisheries. The threshold of memory required for cultural transfer was probably not met—a situation that was further exacerbated by reduced spatiotemporal overlap between older fish and recruits driven by migration constraints and climate change. Finally, a minority of survivors from older generations adopted the migration culture from the recruits instead of the historically opposite. This may have profound consequences for production and coastal ecology, challenging the management of migratory schooling fish.

Stock identification of sympatric Atlantic cod populations in the Gulf of Maine and mixed stock fishery analysis using otolith-based techniques

Article

Full-text available

Oct 2024

Sympatric populations of Atlantic cod with distinct spawning times in winter and spring have been identified within the Gulf of Maine. A new western Gulf of Maine stock assessment unit in U.S. waters lumps winter and spring spawning populations into a single stock unit and future monitoring and assessment of their abundance will require mixed stock analysis. The goal of this study was to evaluate the utility of otolith-based stock identification techniques to discriminate spawning populations. Significant differences in otolith structure and microchemistry were identified between winter and spring spawners with the highest degree of classification accuracy based on both features. Mixed stock analysis applied to fishery samples of unknown origin indicated the contemporary (2015–2016) commercial fishery is dominated by winter spawners. Exploratory classification of historical fishery samples suggested a change over time with spring and winter spawners present in near equal proportion in the early 1990s and winter spawners dominating in the early 1980s. Otolith-based stock composition analysis has the potential to support monitoring and assessment of cod populations in the Gulf of Maine.

Recruitment limitation increases susceptibility to fishing-induced collapse in a spawning aggregation fishery

Article

Full-text available

Jun 2024
MAR ECOL-PROG SER

Spawning aggregation-based fisheries are notorious for booms and busts driven by aggregation discovery and subsequent fishing-induced collapse. However, environment-driven sporadic recruitment in some since-protected populations has delayed recovery, suggesting recruitment-limitation may be a key driver of their population dynamics and fishery recovery potential. To glean insight into this dynamic, we focused on an overexploited temperate aggregate spawner, barred sand bass Paralabrax nebulifer, and leveraged a long-term mark–recapture data set spanning different oceanographic and harvest histories in a custom Bayesian capture–mark– reencounter modeling framework. We coupled this demographic analysis with long-term trends in sea surface temperature, harvest, adult and juvenile densities, and historical accounts in the literature. Our results point to a history of multidecadal windows of fishing opportunity and fishing-induced collapse largely driven by sporadic, warm-water recruitment events, in which recruits may be externally sourced and local recruitment is negatively influenced by harvest. Following the last collapse, recruitment remained elevated due to novel, anomalously warm conditions. Despite signs of incipient population recovery, spawning aggregations remain absent, indicating that other potential factors (e.g. continued fishing during spawning season, Allee effects) have delayed fishery recovery to date. Recruitment-limited aggregate spawner populations, especially those at their geographic margins, are highly susceptible to sudden and potentially extended periods of collapse, making them ill-suited to high catch-per-unit-effort fishing that occurs on spawning grounds. If the goal is to balance protecting spawning aggregations with long-term fishery sustainability, then limiting aggregation-based fishing during the spawning season is likely the best insurance policy against collapse and recovery failure.

Recruitment limitation increases susceptibility to fishing-induced collapse in a spawning aggregation fishery

Preprint

Full-text available

Jun 2024

Spawning aggregation-based fisheries are notorious for booms and busts driven by aggregation discovery and subsequent fishing-induced collapse. However, environment-driven sporadic recruitment in some since-protected populations has delayed recovery, suggesting recruitment-limitation may be a key driver of their population dynamics and fishery recovery potential. To glean insight into this dynamic, we focused on an overexploited temperate aggregate spawner, Barred Sand Bass Paralabrax nebulifer, and leveraged a long-term mark-recapture data set spanning different oceanographic and harvest histories in a custom Bayesian capture-mark-reencounter modeling framework. We coupled this demographic analysis with long-term trends in sea surface temperature, harvest, adult and juvenile densities, and historical accounts in the literature. Our results point to a history of multidecadal windows of fishing opportunity and fishing-induced collapse largely driven by sporadic, warm water recruitment events, in which recruits may be externally sourced and local recruitment is negatively influenced by harvest. Following the last collapse, recruitment remained elevated due to novel, anomalously warm conditions. Despite signs of incipient population recovery, spawning aggregations remain absent, indicating other potential factors (e.g., continued fishing during spawning season, Allee effects) have delayed fishery recovery to date. Recruitment-limited aggregate spawner populations, especially those at their geographic margins, are highly susceptible to sudden and potentially extended periods of collapse, making them ill-suited to high catch-per-unit-effort fishing that occurs on spawning grounds. If the goal is to balance protecting spawning aggregations with long-term fishery sustainability, then limiting aggregation-based fishing during spawning season is likely the best insurance policy against collapse and recovery failure.

Premises for a digital twin of the Atlantic salmon in its world: Agency, robustness, subjectivity and prediction

Article

Full-text available

Feb 2024

Aquaculture of Atlantic salmon Salmo salar is in transition to precision fish farming and digitalization. As it is easier, cheaper and safer to study a digital replica than the system itself, a model of the fish can potentially improve monitoring and prediction of facilities and operations and replace live fish in many what‐if experiments. Regulators, consumers and voters also want insight into how it is like to be a salmon in aquaculture. However, such information is credible only if natural physiology and behaviour of the living fish is adequately represented. To be able to predict salmon behaviour in unfamiliar, confusing and stressful situations, the modeller must aim for a sufficiently realistic behavioural model based on the animal's proximate robustness mechanisms. We review the knowledge status and algorithms for how evolution has formed fish to control decisions and set priorities for behaviour and ontogeny. Teleost body control is through genes, hormones, nerves, muscles, sensing, cognition and behaviour, the latter being agentic, predictive and subjective, also in a man‐made environment. These are the challenges when constructing the digital salmon. This perspective is also useful for modelling other domesticated and wild animals in Anthropocene environments.

Vertebrate decision making leads to the interdependence of behaviour and wellbeing

Article

Mar 2025

Loss of Earth's old, wise, and large animals

Article

Nov 2024
SCIENCE

Earth’s old animals are in decline. Despite this, emerging research is revealing the vital contributions of older individuals to cultural transmission, population dynamics, and ecosystem processes and services. Often the largest and most experienced, old individuals are most valued by humans and make important contributions to reproduction, information acquisition and cultural transmission, trophic dynamics, and resistance and resilience to natural and anthropogenic disturbance. These observations contrast with the senescence-focused paradigm of old age that has dominated the literature for over a century yet are consistent with findings from behavioral ecology and life-history theory. Here, we review why the global loss of old individuals can be particularly detrimental to long-lived animals with indeterminate growth, increasing reproductive output with age, and those dependent on migration, sociality and cultural transmission for survival. Longevity conservation is needed to protect the important ecological roles an ecosystem services provided by old animals.

The Complex World

Book

Sep 2024

David Krakauer

The Complex World, originally published in Volume 1 of Foundational Papers in Complexity Science, presents an entirely new framing of nature, of the human role in the natural and technological worlds, and what it means to prosper on a living planet. We live in a complex world—meaning one that is increasingly connected, evolving, technological, volatile, and potentially poised for catastrophe. And yet we continue to treat the world as if it were simple: linear, unchanging, disconnected, and infinitely exploitable. Complexity science is an approach to understanding and surviving in a complex world. In this concise and comprehensive introduction, Santa Fe Institute President David C. Krakauer traces the roots of complexity science back to the nineteenth-century science of machines—evolved and engineered—into the twentieth-century science of emergent systems. By combining insights from evolution, computation, nonlinear dynamics, and statistical physics, complexity science provides the first scientific framework for understanding the purposeful universe.

The Complex World: An Introduction to the Foundations of Complexity Science

Chapter

May 2024

David Krakauer

Foundational Papers in Complexity Science presents the first unified charting of the full territory of complexity science—an essential resource for navigating the modern world. This project maps the development of complex-systems science through eighty-eight revolutionary works originally published between 1922 and 2000. Curated by SFI President David C. Krakauer, each seminal paper is introduced and placed into its historical context, with enduring insights discussed by leading contemporary complexity scientists. These four volumes are a product of collective intelligence. More than a compilation, Foundational Papers represents large-scale collaboration within the SFI community—brilliant thinkers who have contextualized the work that shaped their own research, resulting in a sparkling demonstration of how complexity shatters the usual scientific divisions and a look back at the path we’ve followed in order to gain a clearer view of what lies ahead.

A dopamine mechanism for reward maximization

Article

May 2024
P NATL ACAD SCI USA

Wolfram Schultz

Individual survival and evolutionary selection require biological organisms to maximize reward. Economic choice theories define the necessary and sufficient conditions, and neuronal signals of decision variables provide mechanistic explanations. Reinforcement learning (RL) formalisms use predictions, actions, and policies to maximize reward. Midbrain dopamine neurons code reward prediction errors (RPE) of subjective reward value suitable for RL. Electrical and optogenetic self-stimulation experiments demonstrate that monkeys and rodents repeat behaviors that result in dopamine excitation. Dopamine excitations reflect positive RPEs that increase reward predictions via RL; against increasing predictions, obtaining similar dopamine RPE signals again requires better rewards than before. The positive RPEs drive predictions higher again and thus advance a recursive reward-RPE-prediction iteration toward better and better rewards. Agents also avoid dopamine inhibitions that lower reward prediction via RL, which allows smaller rewards than before to elicit positive dopamine RPE signals and resume the iteration toward better rewards. In this way, dopamine RPE signals serve a causal mechanism that attracts agents via RL to the best rewards. The mechanism improves daily life and benefits evolutionary selection but may also induce restlessness and greed.

Animal social learning, culture, and tradition.

Chapter

Jan 2017

Overfishing Social Fish

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