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This review was aimed to summarize the extent and causes of fish post‐harvest losses (FPHLs) in Sub‐Saharan African (SSA) countries and suggests the necessary intervention measures to narrow the gap between demand and supply. Globally, an estimate of 10–12 million tons of fish is lost per year. FPHLs in SSA are higher than those in other parts of the world. In SSA, the values of fisheries are estimated at 24 billion USD, 1.26% of the GDP of all the African countries and 6% of agriculture GDP. The vast majority of FPHLs in SSA occur at the production (39%), handling (36%), distribution (13%), processing (7%) and consumption (5%). The major factors that cause FPHLs in SSA were long time spent in hauling of fishing gears, spoilage, size discrimination, species preferences, operational losses, animal predation, poor handling practices, lengthy duration of fishing cycle, failure to use ice, lack of storage facilities, lack of transportation and insect infestation. FPHLs amount one third of total production and financial losses of 2–5 billion USD in SSA countries. Furthermore, volarization of fish waste and converting waste into useful substances is a promising approach to reduce fish waste. It can be recommended that improving fish production, live fish handling, processing, preserving, and marketing in SSA could narrow the gap between fish demand and supply. In SSA, the values of fisheries are estimated at 24 billion USD, 1.26% of the GDP of all African countries and 6% of agriculture GDP. Fish post‐harvest losses amounts an economic losses of 2‐5 billion USD in SSA countries.

In a marine multi-species environment, consumers’ decisions may introduce interactions between species beyond biological ecosystem links. The theoretical literature shows that consumer preferences for variety can trigger a sequential (local) extinction of fish stocks. However, consumer preferences are not yet fully understood empirically, as it is uncertain how variety-loving consumers really are, in particular in specific settings such as in developing countries. In this article, we present an aggregation procedure to study consumer preferences in a highly diverse marine system. In a first step, we use co-integration analysis and aggregation theorems by Hicks and Lewbel to find groups of species that consumers find substitutable. In a second step, we use a direct quadratic almost ideal demand system (QUAIDS) to estimate price elasticities between these groups. We then quantify and compare welfare losses and spillovers from species-specific price shocks that may for example result from restoration efforts. Our case study from Senegal across 28 species reveals evidence that consumers do indeed have a preference for diversity of species on their plates.

This study estimates the price elasticity of demand for Pacific bluefin tuna in Tsukiji Market by using an instrumental variables approach. Variability in catch by purse seine vessels and fluctuations in the auctioned volume at Tsukiji Market are used as supply shocks. This study finds an elastic demand for Pacific bluefin tuna with an estimated constant own-price elasticity of demand of −2.631. There is a growing concern for the health of the Pacific bluefin tuna stock, and management measures are being discussed. This estimation of own-price elasticity of demand for Pacific bluefin tuna can contribute to future policy evaluations. Under elastic demand, a price increase is met with more than a proportionate decrease in the quantity demanded. This may pose as a challenge to the Pacific bluefin tuna fisheries.

The production of farmed fish is growing rapidly and presents a sustainable and possibly low-cost alternative to wild fish. Thus, we may expect retail prices of farmed to be lower than prices of wild fish and demand to be less elastic. Otherwise, marketing of farmed fish may generate some extra value that justifies higher prices and may exhibit more elastic demand. To test these hypotheses, we employ monthly household scanner panel data for Germany from 2006 to 2010 for six frozen seafood products that include farmed and wild fish. A QUAIDS model is estimated by a consistent two-step procedure to account for censoring of the dependent variable. We find consumers to be price sensitive, particularly with regard to the high-value seafood species salmon and shrimp. This price elastic market implies that the German seafood industry still has the potential for growing revenues if production increases. JEL Codes: C32, C33, D12, Q22.

This study was conducted to estimate the elasticities of demand for eight different fish types and four income groups in Bangladesh using year-round data collected from inland areas of the country. It uses a three-stage budgeting framework that estimates a demand function for food in the first stage, a demand function for fish (as a group) in the second stage, and a set of demand functions for fish by type in the third stage using a quadratic extension of the Almost Ideal Demand System (QUAIDS) model. The Heckman procedure was used in stage three to remove the possible bias in the parameter estimates brought about by zero consumption. The magnitude of both price and income elasticities varies across different fish types and income quartile groups, indicating the relevance of estimation specific to fish types and quartiles. Except for assorted small fish, the other seven fish types included in the study were found to have positive income elasticity for all income levels. Assorted small fish is an inferior commodity for the richest quartile of the population.

In recent years, the theoretical restrictions of consumer demand have been examined in post-sample forecasting exercises. However, this work has uniformly ignored associated curvature restrictions. In this paper we evaluate a series of Normalized Quadratic Inverse Demand System (NQIDS) specifications by using rolling windows and generating one- to four-step ahead forecasts. Data for eleven categories of South Atlantic fish spanning 1980 through 2001 are used in estimation. In addition to the NQIDS, we also examine the forecasting performance of a Cobb–Douglas model with autoregressive errors. We find that the best predictions are achieved using a composite forecast.

We analyze demand substitution relationships among fish in the snapper/grouper complex in the southeast United States. Monthly data from 1977 to 1992 are used to form a set of six fish aggregates. The dockside demands are analyzed in an empirical inverse demand system, developed for the purposes of this study. Attention is paid to consistency of the system with the theory of demand, to functional form flexibility, and to consistent estimation of parameters. Empirical results imply that the demands have small quantity elasticities, which can be thought of as high price elasticities in a direct demand system. Regulatory variations in landed quantities have little measured effect on prices, implying that market prices are good per-unit measures of the welfare costs of catch restrictions to consumers. Welfare estimates of hypothetical harvest reductions are computed and illustrated.

Over the past 20 years, the demand for fish in the UK has changed markedly. The species prevalent in the consumption mix has altered to reflect the greater availability of farmed species and the decline in some marine-caught species. This paper examines the retail demand for fish in the UK and the implications this has for fisheries policy. A two-stage demand model using a dynamic Almost Ideal Demand System (AIDS) is estimated from retail panel data for fish and fish products in Great Britain.¹ Both conditional and unconditional expenditure, own- and cross-price elasticities of demand are derived from the parameter estimates. Haddock, salmon, flatfish, shellfish, and smoked fish are expenditure elastic, implying that income growth will strongly increase demand for these species. Most species are own-price inelastic, suggesting that policy-driven catch restrictions can increase expenditure on fish and may reduce the short-run incentives of commercial fishermen to comply.

This chapter contains sections titled: Introduction Mechanisms Development Functions Implications for aquaculture Synopsis References