Reticulated knifefish

Papyrocranus afer

Papyrocranus afer (Reticulated knifefish)
Distribution
Distribution map: Papyrocranus afer (Reticulated knifefish)

least concern



Information


Author: María J. Cabrera-Álvarez
Version: C | 1.0 (2022-12-30)

Please note: This part of the profile is currently being revised.


Reviewers: N/A
Editor: Jenny Volstorf

First published: 2022-12-30
Version information:
  • Appearance: C
  • Major version 1 published: 2022-12-30

Cite as: »Cabrera-Álvarez, María J.. 2022. Papyrocranus afer (Farm: Short Profile). In: fair-fish database, ed. fair-fish. World Wide Web electronic publication. First published 2022-12-30. Version C | 1.0. https://fair-fish-database.net.«





FishEthoScore/farm

Papyrocranus afer
LiPoCe
Criteria
Home range
Depth range
Migration
Reproduction
Aggregation
Aggression
Substrate
Stress
Malformations
Slaughter


Condensed assessment of the species' likelihood and potential for good fish welfare in aquaculture, based on ethological findings for 10 crucial criteria.

Li = Likelihood that the individuals of the species experience good welfare under minimal farming conditions
Po = Potential of the individuals of the species to experience good welfare under high-standard farming conditions
Ce = Certainty of our findings in Likelihood and Potential

FishEthoScore = Sum of criteria scoring "High" (max. 10)

Legend

High
Medium
Low
Unclear
No findings



General remarks

Papyrocranus afer is a freshwater species that inhabits rivers and lakes of the tropical West Africa. P. afer's natural populations are endangered due to overfishing, industrialisation, anthropogenic activities, and collection as ornamental FISHES for aquaria. Culture of P. afer has become popular to supply food for the local communities as well as to protect the natural populations by supplying the demand of this species as ornamental fish. However, very little is know about its culture conditions and more research needs to be done in all criteria, both for farming conditions and wild environment.




1  Home range

Many species traverse in a limited horizontal space (even if just for a certain period of time per year); the home range may be described as a species' understanding of its environment (i.e., its cognitive map) for the most important resources it needs access to. What is the probability of providing the species' whole home range in captivity?

There are no findings for minimal and high-standard farming conditions.

Likelihood
Potential
Certainty

Eggs: does not apply.

LARVAE and FRY:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: does not apply.

JUVENILES:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: does not apply.

ADULTS:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: does not apply.

SPAWNERS:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: does not apply.



2  Depth range

Given the availability of resources (food, shelter) or the need to avoid predators, species spend their time within a certain depth range. What is the probability of providing the species' whole depth range in captivity?

There are unclear findings for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.

Likelihood
Potential
Certainty

Eggs:

  • WILD: rivers: 2 m 1 2 with unclear depth range use.
  • FARM: no data found yet.
  • LAB: does not apply.

LARVAE and FRY:

  • WILD: Eggs.
  • FARM: no data found yet.
  • LAB: does not apply.

JUVENILES:

  • WILD: Eggs.
  • FARM: no data found yet.
  • LAB: does not apply.

ADULTS:

  • WILD: rivers: 2 m 1 2 with unclear depth range use. Feed at surface, midwater, and bottom 1.
  • FARM: no data found yet.
  • LAB: does not apply.

SPAWNERS:

  • WILD: Eggs.
  • FARM: no data found yet.
  • LAB: does not apply.



3  Migration

Some species undergo seasonal changes of environments for different purposes (feeding, spawning, etc.) and with them, environmental parameters (photoperiod, temperature, salinity) may change, too. What is the probability of providing farming conditions that are compatible with the migrating or habitat-changing behaviour of the species?

There are unclear findings for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.

Likelihood
Potential
Certainty

Eggs: does not apply.

LARVAE and FRY:

  • WILD: rivers: 23.3-28.0 °C 1 2.
  • FARM: no data found yet.
  • LAB: no data found yet.

JUVENILES:

  • WILD: rivers: 23.3-28.0 °C 1 2. Nocturnal 3 4.
  • FARM: no data found yet.
  • LAB: no data found yet.

ADULTS:

  • WILD:  JUVENILES.
  • FARM: no data found yet.
  • LAB: no data found yet.

SPAWNERS:

  • WILD:  LARVAE and FRY.
  • FARM: no data found yet.
  • LAB: no data found yet.



4  Reproduction

A species reproduces at a certain age, season, and sex ratio and possibly involving courtship rituals. What is the probability of the species reproducing naturally in captivity without manipulation?

There are unclear findings for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.

Likelihood
Potential
Certainty

Eggs: does not apply.

LARVAE and FRY: does not apply.

JUVENILES: does not apply.

ADULTS: does not apply.

SPAWNERS:

  • WILD: breeding season: Aug-Nov 5-6.
  • FARM: no data found yet.
  • LAB: reproduction not reported in captivity 3 7.



5  Aggregation

Species differ in the way they co-exist with conspecifics or other species from being solitary to aggregating unstructured, casually roaming in shoals or closely coordinating in schools of varying densities. What is the probability of providing farming conditions that are compatible with the aggregation behaviour of the species?

There are unclear findings for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.

Likelihood
Potential
Certainty

Eggs: does not apply.

LARVAE and FRY:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet

JUVENILES:

  • WILD: solitary 1.
  • FARM: no data found yet.
  • LAB: no data found yet.

ADULTS:

  • WILD:  JUVENILES.
  • FARM: no data found yet.
  • LAB: no data found yet.

SPAWNERS:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.



6  Aggression

There is a range of adverse reactions in species, spanning from being relatively indifferent towards others to defending valuable resources (e.g., food, territory, mates) to actively attacking opponents. What is the probability of the species being non-aggressive and non-territorial in captivity?

There are unclear findings for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.

Likelihood
Potential
Certainty

Eggs: does not apply.

LARVAE and FRY:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.

JUVENILES:

  • WILD: no data found yet.
  • FARM: aggressive and territorial 3 4. Aquaria: can be kept in small groups 7 4.
  • LAB: no data found yet.

ADULTS:

  • WILD: no data found yet.
  • FARM: aggressive and territorial  3 7 4.
  • LAB: no data found yet.

SPAWNERS:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.



7  Substrate

Depending on where in the water column the species lives, it differs in interacting with or relying on various substrates for feeding or covering purposes (e.g., plants, rocks and stones, sand and mud). What is the probability of providing the species' substrate and shelter needs in captivity?

There are unclear findings for minimal and high-standard farming conditions. Our conclusion is based on a low amount of evidence.

Likelihood
Potential
Certainty

Eggs:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.

LARVAE and FRY:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.

JUVENILES:

  • WILD: sand 1 8 9, mud 1 9, clay, shale, silt 9. Quiet, gently-flowing vegetated areas 1 10 11 8 2, avoiding open water 1, low canopy closure, high temperature, high total dissolved solids 10.
  • FARM: no data found yet.
  • LAB: no data found yet.

ADULTS:

  • WILD:  JUVENILES.
  • FARM: no data found yet.
  • LAB: no data found yet.

SPAWNERS:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.



8  Stress

Farming involves subjecting the species to diverse procedures (e.g., handling, air exposure, short-term confinement, short-term crowding, transport), sudden parameter changes or repeated disturbances (e.g., husbandry, size-grading). What is the probability of the species not being stressed?

There are no findings for minimal and high-standard farming conditions.

Likelihood
Potential
Certainty

Eggs:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.

LARVAE and FRY:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.

JUVENILES:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.

ADULTS:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.

SPAWNERS:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.



9  Malformations

Deformities that – in contrast to diseases – are commonly irreversible may indicate sub-optimal rearing conditions (e.g., mechanical stress during hatching and rearing, environmental factors unless mentioned in crit. 3, aquatic pollutants, nutritional deficiencies) or a general incompatibility of the species with being farmed. What is the probability of the species being malformed rarely?

There are no findings for minimal and high-standard farming conditions.

Likelihood
Potential
Certainty

Eggs:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.

LARVAE and FRY:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.

JUVENILES:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.

ADULTS:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.

SPAWNERS:

  • WILD: no data found yet.
  • FARM: no data found yet.
  • LAB: no data found yet.



10  Slaughter

The cornerstone for a humane treatment is that slaughter a) immediately follows stunning (i.e., while the individual is unconscious), b) happens according to a clear and reproducible set of instructions verified under farming conditions, and c) avoids pain, suffering, and distress. What is the probability of the species being slaughtered according to a humane slaughter protocol?

There are no findings for minimal and high-standard farming conditions.

Likelihood
Potential
Certainty

Eggs: does not apply.

LARVAE and FRY: does not apply.

JUVENILES:

  • WILD: does not apply.
  • FARM: no data found yet.
  • LAB: no data found yet.

ADULTS:

  • WILD: does not apply.
  • FARM: no data found yet.
  • LAB: no data found yet.

SPAWNERS:

  • WILD: does not apply.
  • FARM: no data found yet.
  • LAB: no data found yet.



Side note: Domestication

Teletchea and Fontaine introduced 5 domestication levels illustrating how far species are from having their life cycle closed in captivity without wild input, how long they have been reared in captivity, and whether breeding programmes are in place. What is the species’ domestication level?

DOMESTICATION LEVEL 3 12, level 5 being fully domesticated.




Side note: Forage fish in the feed

450-1,000 milliard wild-caught fishes end up being processed into fish meal and fish oil each year which contributes to overfishing and represents enormous suffering. There is a broad range of feeding types within species reared in captivity. To what degree may fish meal and fish oil based on forage fish be replaced by non-forage fishery components (e.g., poultry blood meal) or sustainable sources (e.g., soybean cake)?

All age classes:

  • WILD: carnivorous 1 13 14: fish, insects, shrimps, crabs, worms 1 13 14, partly herbivorous 1.
  • FARM: no data found yet.
  • LAB: no data found yet.



Glossary


ADULTS = mature individuals, for details Findings 10.1 Ontogenetic development
DOMESTICATION LEVEL 3 = entire life cycle closed in captivity with wild inputs 12
FARM = setting in farming environment or under conditions simulating farming environment in terms of size of facility or number of individuals
FISHES = Using "fishes" instead of "fish" for more than one individual - whether of the same species or not - is inspired by Jonathan Balcombe who proposed this usage in his book "What a fish knows". By referring to a group as "fishes", we acknowledge the individuals with their personalities and needs instead of an anonymous mass of "fish".
FRY = larvae from external feeding on, for details Findings 10.1 Ontogenetic development
JUVENILES = fully developed but immature individuals, for details Findings 10.1 Ontogenetic development
LAB = setting in laboratory environment
LARVAE = hatching to mouth opening, for details Findings 10.1 Ontogenetic development
SPAWNERS = adults during the spawning season; in farms: adults that are kept as broodstock
WILD = setting in the wild



Bibliography


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2 Usanga, Ekpeno Etiese. 2015. Abundance and Monthly Composition of Fish Species of Ikpa River at Ntak Inyang, Akwa Ibom State, Nigeria. Journal for Studies in Management and Planning 1: 239–247.
3 Hvizdak, Jan. 2014. A page dedicated to keeping Reticulate knifefish (Papyrocranus afer). Aqua-fish.net.
4 aquaristsacrosscanada.com. 2022. RETICULATED KNIFE FISH (Papyrocranus afer). Aquarists Across Canada. https://aquaristsacrosscanada.com/products/reticulated-knife-fish-papyrocranus-afer. Accessed November 2.
5 Planquette, P., and J. Lemasson. 1975. Le peuplement de poissons du Bandama blanc en pays Baoulé. Ann. Univ. Abidjan, sér E, Ecologie 8: 77–121.
6 Albaret, Jean-Jacques. 1982. Reproduction et fécondité des poissons deau douce de Côte dIvoire. Rev. Hydrobiol. trop. 15: 347–371.
7 seriouslyfish.com. 2022. Papyrocranus afer (Arowana Knifefish, Reticulate Knifefish, Marbled Knifefish) — Seriously Fish.
8 Adaka, Godwin, Eunice Ndukwe, and Anthony Nlewadim. 2015. Length-Weight Relationship of Some Fish Species in a Tropical Rainforest River in South-East Nigeria. Transylvanian Review of Systematical and Ecological Research 17: 73–78. https://doi.org/10.1515/trser-2015-0065.
9 Nwamaka, Keziah, and Prudentia Ogochukwu. 2017. FISH COMMUNITY STRUCTURE IN A NATURAL RAINFOREST LAKE, NIGERIA. Animal Research International.
10 Kouamé, Kouakou Augustin, Stanislas Silvain Yao, Gouli Gooré Bi, Essetchi Paul Kouamélan, Valentin N’Douba, and N’Guessan Joël Kouassi. 2008. Influential environmental gradients and patterns of fish assemblages in a West African basin. Hydrobiologia 603: 159–169. https://doi.org/10.1007/s10750-007-9256-1.
11 Lin, Yu-Jia. 2010. A brief guide to the Fishes in Sapu and nearby regions, Central River Region, The Gambia. Taiwan Technical Mission in The Gambia, Sapu, Central River Region, The Gambia, West Africa. Gambia, West Africa.
12 Teletchea, Fabrice, and Pascal Fontaine. 2012. Levels of domestication in fish: implications for the sustainable future of aquaculture. Fish and Fisheries 15: 181–195. https://doi.org/10.1111/faf.12006.
13 Edema, C. U., and M. O. Aiguobasinmwin. 2008. Determination of intestine length to standard length ratio of some fishes from Ikpoba River and Ovia River, Nigeria with a review of culture of Parachanna obscura (Pisces: Channidae).
14 Oribhabor, Blessing J., Aniekan E. Akpan, and Gift S. David. 2019. The Food and Feeding Habits of Fishes of a Coastal Nigeria River. Scientific Research Journal VII. https://doi.org/10.31364/SCIRJ/v7.i9.2019.P0919697.


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