Assalamualaikum ustaz. What is the ruling of eating otter? Thank you.
Waalaikumussalam wrt. wbt.,
Alhamdulillah, praise and gratitude to Allah SWT for His countless blessings for us all. Praise and salutations to our beloved Prophet Muhammad PBUH, his family, companions, and all those who follow his footsteps until the Final day.
وَيُحِلُّ لَهُمُ الطَّيِّبَاتِ وَيُحَرِّمُ عَلَيْهِمُ الْخَبَائِثَ
“And makes lawful for them the good things and prohibits for them the evil,” 
This verse shows that everything that is made permissible is good and considered acceptable according to the norm, except if there is other evidence that states that it is prohibited. Likewise, anything that is prohibited is everything that is considered filthy and disgusting naturally such as carcass and blood and the people who eat it are considered fasiq. In other words, everything that is considered filthy naturally by mankind is prohibited because it is a cause of disease. Hence, anything that is harmful is originally prohibited. Thus, anything that is naturally filthy is originally prohibited except when there is evidence stating otherwise. 
Definition of otter and its habitat
Otters are mostly aquatic carnivorous mammals (such as the genus Lutra or Enhydra) from the weasel family that usually have webbed feet and claws and dark brown fur. 
Generally, otters will start hunting in the early morning and late afternoon. But there are also those who hunt at night. The main food of otters is fish. However, they are not fussy in choosing food. They will eat whatever they find in order to survive such as invertebrates (animals that have no backbone), birds, frogs, crabs, crayfish and smaller animals (than them). They also eat lizards and others found on land, if necessary.  In fact, some species of beavers have been identified as no longer catching fish-that is, leaving them simply to hunt rabbits. 
Sea otters can stay in the water for more than 5 minutes at a time. However, river otters can hold their breath while in the water for up to 8 minutes. 
Animals that live in both sea and on land
Regarding this matter, Dr Wahbah al-Zuhaili cited the opinion of scholars from madhhab Hanafi and Syafi’I who stated that it is impermissible to eat any animal that lives on land and in water for it is considered filthy and disgusting.  Furthermore, Syeikh al-Islam Zakaria al-Ansari also cited the opinion of Imam al-Mawardi that set the dhawabit (guidelines) in determining the category of a certain animal when both the land and sea are gathered, which are:
مَا يَجْمَعُ مِنْ الْحَيَوَانِ بَيْنَ الْبَحْرِ وَالْبَرِّ إنْ كَانَ اسْتِقْرَارُهُ بِأَحَدِهِمَا أَغْلَبَ وَمَرْعَاهُ بِهِ أَكْثَرَ غَلَبَ عَلَيْهِ حُكْمُهُ
“An animal that is gathered the sea and land (can live in both), if it can stay (continuously) alive in one of them usually and live there most of the time. Then, its ruling follows what is the usual for it.”
Hence, any animal that couldn’t live except in water or when it is not in water then it can only live like a slaughtered animal, then it is permissible to be eaten, no matter what is the situation and it is considered a marine animal. Then, if the animal isn’t inclined towards any one of them (land or sea), then its ruling follows land animal according to a sahih opinion and it is impermissible to be eaten except after it is slaughtered if it is included as an animal that can be slaughtered. If not, then it is prohibited – to be eaten. 
However, regarding this matter, Imam al-Nawawi concluded by saying that the sahih and final opinion is that all marine animals, their carcass is halal – to be eaten – except frogs. Then it can be understood that what is stated by scholars of madhhab Syafi’I or a part of them regarding the prohibition of turtles, snakes and nasnas that live in water other than the sea.  In other words, there is a possibility that there are other factors that lead to the prohibition such as evidence that prohibits it, it is harmful or others.
This can be understood clearly through a statement made by Dr Muhammad al-Zuhaili who said that frog is prohibited because there is evidence stating that frogs are prohibited to be eaten because there is evidence commanding to kill frogs. While snakes and crabs are because they are poisonous and considered filthy. Furthermore, it is also prohibited from eating crocodiles because they hunt their prey using their incisors. 
The ruling of eating otters
Regarding this matter, most scholars are of the opinion otters are prohibited to be eaten because they are categorized as an animal that lives on land and in water as cited by Syeikh Daud al-Fatani in his book.  The next question that arises is, is it true that otters are categorized as an animal that lives on land and in water? When the facts and habitat are considered, otters aren’t animals that live both on land and in water, for they cannot live long underwater. Hence, it is more accurate to state that otters are land mammals that can hunt underwater for a limited amount of time.
Even if this is so, we still believe that the meat of otters is prohibited, for an otter is categorized as a wild animal that has strong incisors to hunt and catch its prey. This is as stated in a narration from Abu Tha’labah:
نَهَى النَّبِيُّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ عَنْ أَكْلِ كُلِّ ذِي نَابٍ مِنَ السَّبُعِ
“The Messenger of Allah (ﷺ) prohibited eating fanged beasts of prey.” 
Imam al-Syafi’I further explained this matter by saying that fanged animals that are prohibited to be eaten are those who hunt their prey with their incisors.  Thus, if there are other fanged animals but they aren’t included in this prohibition is because they have weak incisors and don’t use them to hunt other animals as food. Thus, although otters aren’t categorized as animals that live both on land and in water, they are still prohibited because they are categorized as wild fanged animals that have strong incisors to hunt their prey.
Especially, when otters are also categorized as protected wildlife as provided in Act 716 which is the Wildlife Conservation Act. The First Schedule (section 3), Part 2 has stated that animals from the Mustelidae family such as Lontra Canadensis (River Otter), Lutra (Otters) and others are included in other protected wildlife species.  Similarly, the Second Schedule (section 3) which is fully protected wildlife, has included a large number of animals from this family such as the small beaver (Aonyx cinerea), northern beaver (lutra lutra), hairy-nosed beaver (lutra sumatrana), and others. 
Hence, one cannot simply hunt, catch or trap these animals. If one is convicted for the offence, he is punishable by law as stated in the act.
In this issue, the authorities have the right to issue a decision in order to protect the greater maslahah. This is in line with a famous Islamic legal maxim:
تَصَرُّفُ الْإِمَامِ عَلَى الرَّعِيَّةِ مَنُوطٌ بِالْمَصْلَحَةِ
“The policy of a government must be based on the maslahah of the people.”
Hence, it is the responsibility of the people to obey and support the ulil amri in makruf (good) matters.
According to the above arguments and discussion, in our opinion, otters are prohibited to be eatn because they are categorized as fanged animals that use their fangs to hunt other animals as their main diet.
Furthermore, otters are also a protected wildlife as provided in Act 716, for they are among the endangered species. Hence, it is our responsibility to ensure the continuity of its generation so that our future generation will be able to see and know them.
May Allah SWT grant us all a clear understanding in this religion. Amin.
 Surah al-A‘raf : 157
 See Mafatih al-Ghaib, 15/381.
See Merriam-Webster Dictionary, https://www.merriam-webster.com/dictionary/otter.
See Otter-World, https://www.otter-world.com/otter-feeding/. Also see, Seaworld Parks & Entertainment, https://seaworld.org/animals/all-about/otters/diet/.
 See Discover Wildlife, https://www.discoverwildlife.com/animal-facts/mammals/otters-of-the-world/.
See 12 Facts about Otters for Sea Otter Awareness Week, https://www.doi.gov/blog/12-facts-about-otters-sea-otter-awareness-week.
 See al-Fiqh al-Islami wa Adillatuh, 4/2799.
 See Asna al-Matalib, 1/566.
 See al-Majmu‘ Syarh al-Muhazzab, 9/32-33.
 See al-Mu‘tamad fi al-Fiqh al-Syafi‘i, 2/548-549.
 See Matla‘ al-Badrain, (arranged by PMWP), 2/25.
 Riwayat Muslim (1932)
 See al-Umm, 2/272.
 See Akta 716, pg. 106.
 See Akta 716, pg. 145.