General Outline What are fisheries? 1. Introduction Definition: - PDF document

General Outline What are fisheries? 1. Introduction • Definition: an entity representing the harvest animals from aquatic environments 2. Fisheries Science • Exploitation 3. Effects of Fishing – Economics 4. Fisheries – Biology Management – Societal Aspects a. Politics • Conservation b. Economics • Politics • Regulation c. Societal Aspects Types of Fisheries: How to catch a fish • Hooks • Artisanal: traditional fishing effort involving – Rod and reel households; small-scale in economic input and – Longlines effort; often associated with subsistence fishing, • Traps may be commercial in nature; usually local in • Nets effect. - Seines - Gill nets • Commericial: capitalization of catch with a larger- - Trawls scale economic input and effort; usually larger - Etc. than household group. • Projectiles – Spears • Recreational: fishing for sport – Harpoons • Alternative methods – e.g. Dyn-o-mite

History of Fishing Fundamental Problems • Earliest fishing implements – bone harpoons (90,000 yrs old) from Congo (2-m long catfish) • Overcapitalization • Artisanal fishing efforts – extinction of Stellar Sea Cows • Overfishing (1768) • Long-term damage to marine ecosystems • 1700-1900s: Whales, Seals, Otters, Turtles, Cod, Herring, Haddock, etc. • Extinction • Industrial Revolution and Technological Advancement –Steam engine –Fleet development –Refrigeration –Transportation –Navigation Biological theory of exploitation Tragedy of the commons • Garret Hardin, Science (1968) change of N per time t Yield • Scramble competition: when (Surplus of population) many share a resource, the population resource is at strong risk to get growth rate depleted (= species goes extinct) because the economical strategy is to get more than the others (=maximize gain). • We see this problem in hunting/ fishing but also on grazing on N=population size public land. K=Carrying capacity Fisheries Science • Roots in Population Ecology • Applied ecological research that provides information for management structures • Empirical Work • Modeling • The logistic growth function can be – Stock Assessments solved for Y and so we can get the surplus – Compensation/Depensation – Allee Effect for known K and r.

The Models: Summarized Evolution of models reflects the evolution of our understanding of these systems • length–age • weight–length • fecundity–length • maturity–age • Maximum Sustainable Yield (MSY): Maximum use that a renewable • spawner–recruit resource can sustain without impairing its renewability through natural • selectivity–age growth or replenishment • Total Allowable Catch (TAC): Amount of catch managers allow to be Classical Neo-Classical taken EBM • - 1970s and early: logistic growth model, deterministic, no • length–age Ecosystem-Based environmental or stochastic variation • weight–length • fecundity–length Approaches • - 1980s: depensation – low survival at low density, stochasticity in • maturity–age early life history, maximize MSY • spawner–recruit Hmmmm… • - 1990s: precautionary – use MSY as limit • selectivity–age • - 2000s: ecological considerations • stochasticity • species interactions Modern • environmental interactions Fisheries Impact: Oops…forgot about all that pesky Biology “ I believe that the cod fishery, the herring fishery, the pilchard fishery, the mackerel fishery, and probably all the great sea-fisheries are inexhaustible; that is to say, nothing we can do seriously affects the number of fish (Thomas Huxley 1883)” Peruvian Anchovy Fishery Status of Fisheries Impact: Global Marine Fisheries Trends Oops…forgot about all that pesky Biology “ I believe that the cod fishery, the herring fishery, the pilchard fishery, the mackerel fishery, and probably all the great sea-fisheries are inexhaustible; that is to say, nothing we can do seriously affects the number of fish (Thomas Huxley 1883)” • Extinctions due to overfishing • Numerical • Ecological • By-Catch – catch of non-target species (generally discarded) • Economic Collapse • Habitat Degradation • Reduced Ecosystem stability

U – underexploited D – moderately exploited M – fully exploited S – overfished R – recovering

Fishing Down the Food Web Why did this happen? Food Web • Inaccurate estimates of population sizes – Models descriptive, not predictive 3.8 • Parameters inaccurate (e.g. Catch-per-unit-effort (CPUE)) 3.1 – Biology of species can drastically affect the assumptions of these models – Use of destructive fishing practices – Ignorance of ecosystem affects 2.3 • Inappropriate economic incentives 2 2.3 • Lack of political/social will Example: New England Groundfish and Lobsters Reductions of Top-Level Predators 2004 Catch: $253.5 million 62 million lbs. Age distributions and reproduction photo from www.daisymaefishing.com

Life History Strategies: Example: Rockfish Larval Abundances Age-structured schedules of mortality and reproduction • Long-lived: late age at first reproductive maturity • Aggregation • Low intrinisic rate of increase – offspring number • Differential reproductive value to older individuals • Strong association with specific habitat The Economic Issues Example: Red Hinds and Nassau Groupers in Bermuda • Scramble Competition (Tragedy of the Commons) – No advantage to helping your neighbor – No advantage to saving for later • Unlimited access • Growing demand on limited resources • Subsidies that stimulate overcapacity • Ignorance about impact

Modern approaches: Despite improvements in science, lag in action and lack of Access Closed management cycle causes problems • Traditonal tools: – Gear restrictions – Regulation of Catch and effort • Access structure (limited entry into the race-to- fish): – Limited entry • Regulate number of licenses • Marine Protected Areas (MPAs) – Individual quotas (IQs) • Transferable (ITQs) • Vessel (IVQs) Modern approaches: Modern approaches: Decision Making Spatial Scales • “Minister of Fisheries” (United Kingdom) – Ultimate authority lies with the minister • Unit Stock • Council (USA) – Fisheries can be defined into discrete independent units – Not biological or economically accurate – Appointed individuals from various sectors; try to build consensus but ruled by majority vote – Evolutionary Significant Unit (ESU): • (1) Substantially reproductively isolated from other conspecific • Commission (international) population units – Representatives from membership councils • (2) Represent an important component in the evolutionary legacy of a species • All entities beginning to adhere to precautionary • Metapopulations axioms (risk management) – population consists of interacting sub-populations – extinction/colonization – source-sink dynamics